一年级数学第一册第八单元教案
一年级上册数学教案-第八单元第一课时20以内的进位加法人教新课标
一年级上册数学教案第八单元第一课时 20以内的进位加法人教新课标我教学的是人教新课标一年级上册数学教案，第八单元的第一课时，主题是20以内的进位加法。
一、教学内容我教的内容包括教材的第73页例1以及第74页的“做一做”和练习十二的第1题。
这些题目主要让学生掌握20以内的进位加法。
二、教学目标通过这节课的学习，我希望学生们能够理解20以内的进位加法的概念，并且能够独立完成相关的计算。
三、教学难点与重点重点是让学生掌握进位加法的计算方法，难点是让学生能够理解进位的概念。
四、教具与学具准备我准备了一些计数棒和算术卡片，让学生们可以直观地看到加法的运算过程。
五、教学过程我会用计数棒演示20以内的加法，让学生们有一个直观的认识。
然后，我会讲解例1，让学生们明白进位加法的概念。
接着，我会让学生们做“做一做”的题目，巩固他们对于进位加法的理解。
我会让学生们做练习十二的第1题，检验他们对于进位加法的掌握。
六、板书设计我会设计一个简洁明了的板书，将进位加法的计算方法清晰地展示给学生。
七、作业设计作业题目：完成练习十二的第2题。
答案：略八、课后反思及拓展延伸课后，我会反思我这节课的教学效果，看看学生们对于进位加法的掌握情况。
同时，我也会寻找一些拓展延伸的材料，让有兴趣的学生可以进一步深入学习。
这就是我对于这节课的教学设计，我希望通过这样的设计，让学生们能够真正理解并掌握20以内的进位加法。
重点和难点解析在上述教学设计中，有几个关键的细节是我需要特别关注的。
这些细节对于学生理解和掌握20以内的进位加法至关重要。
我需要重点关注的是教学内容的选取。
我选择了教材的第73页例1以及第74页的“做一做”和练习十二的第1题作为教学内容。
这些题目覆盖了20以内的进位加法的基本概念和计算方法。
通过这些题目，学生们可以逐步理解和掌握进位加法的运算过程。
我需要重点关注的是教学目标的设定。
我希望学生们能够理解20以内的进位加法的概念，并且能够独立完成相关的计算。
一年级上数学教案-第八单元20以内的进位加法-人教新课标
一年级上数学教案第八单元 20以内的进位加法人教新课标我今天要为大家带来的是人教新课标一年级上数学教案中第八单元的教学内容，主题是20以内的进位加法。
一、教学内容我们今天的学习重点是20以内的进位加法，主要涉及到教材中第八章的内容，包括加法的概念，进位加法的运算方法，以及20以内的加法表。
二、教学目标通过今天的学习，我希望同学们能够理解进位加法的概念，掌握20以内的进位加法运算方法，并能够熟练运用20以内的加法表进行计算。
三、教学难点与重点今天的教学难点是理解进位加法的运算规律，以及掌握20以内的加法表。
而教学重点则是让同学们能够熟练地进行20以内的进位加法运算。
四、教具与学具准备为了帮助同学们更好地理解进位加法，我准备了一些教具和学具，包括黑板、粉笔、加法表格、计算器以及一些小玩具。
五、教学过程1. 实践情景引入：我会通过一些实际生活中的例子，如购物时需要进行找零等，引入进位加法的学习。
2. 概念讲解：然后我会利用教具和学具，向同学们讲解进位加法的概念和运算方法。
4. 随堂练习：在讲解完例题后，我会组织同学们进行一些随堂练习，以巩固他们对于进位加法的理解和掌握。
5. 加法表格：我会引导同学们学习和使用20以内的加法表格，以提高他们的计算速度和准确性。
六、板书设计在讲解的过程中，我会利用黑板和粉笔，将一些重要的概念和运算方法进行板书，以帮助同学们更好地理解和记忆。
七、作业设计答案：12+5=17，18+4=22，23+6=29。
2. 请同学们根据下面的情境，完成进位加法的计算：妈妈买了3个苹果和4个香蕉，一共有几个水果？答案：3+4=7，一共有7个水果。
八、课后反思及拓展延伸通过今天的学习，我希望同学们能够理解进位加法的概念，掌握20以内的进位加法运算方法，并能够熟练运用20以内的加法表进行计算。
同时，我也希望同学们能够通过作业的练习，巩固所学的内容，并能够将所学运用到实际生活中。
对于拓展延伸部分，同学们可以尝试自己创造出一些进位加法的题目，并与同学们进行交流和解答。
一年级数学第8单元教案5篇
一年级数学第8单元教案5篇当一个学生被迫大展身手去对付未解决的问题时，比仅仅学习数学知识，其受益要多得多。
为了大家学习方便，笔者特地准备了一年级数学第8单元教案5篇，希望可以帮助大家，欢迎借鉴学习!一年级数学第8单元教案1教学目标：1、使学生结合生活经验，初步认识钟面，会认读整时、半点。
2、在具体情境中，培养学生珍惜时间的观念和合理安排时间的良好习惯。
3、培养学生初步的观察分析能力，体验与他人合作交流的乐趣。
教学重点：根据情境图提出数学问题，培养学生解决问题的能力。
教学难点：初步认识钟面，会认读整时、半时。
教具准备：钟模型、多媒体课件。
一、猜谜创设情境，激趣导入。
师：同学们，你们喜欢猜谜语吗?老师就给大家带来了一个谜语，想猜吗?“滴哒滴哒，滴哒滴哒，会说没有嘴，会走没有腿，它能告诉我们，什么时候睡，什么时候起”能告诉我谜底是什么吗?生：钟表答对了。
这节课我们就共同来“认识钟表”(板书课题)师：今天老师请来了一位新朋友，他的名字叫小明，和大家一样，也上一年级了。
他今天有一个问题想请教一下大家，大家愿不愿意帮助他呢?1、播放课件，提出问题。
2、我们看看这个方法行不行呢，继续看课件。
有了这个钟表，小明的生活发生了很大的变化，我们这节课就来了解一下“小明的一天”。
二、合作交流，总结经验1、认识钟面①师：生活中我们经常见到钟表，那么钟面上有什么呢?请大家认真观察手中的学具钟面，说一说你发现了什么。
②师小结：小老师们懂得真不少，有的不仅会看钟面上的时间，还知道钟面上(出示钟面实物图)有12个数，有3根指针，又短又粗的一根叫时针，长一些的这根叫分针，最长的这根叫秒针。
(过渡：我们认识了时针和分针，你知道这些表的时间吗?)2、观察情境图，交流经验(1)。
认读整时、半点①屏幕出示“小明的一天”的生活情境。
师：这是小明一天的生活安排，请小朋友们试着在小组里说一说小明什么时间在做什么，你是怎样看钟面上的时间的?师：谁来介绍小明在一天都做了些什么?师：介绍得真清楚。
人教版小学一年级数学上册第八单元《20以内的进位加法》教案
人教版小学一年级数学上册第八单元《20以内的进位加法》教案一. 教材分析《20以内的进位加法》是人教版小学一年级数学上册第八单元的内容，主要让学生掌握加法的基本运算方法，学会将两个数相加，并能够进行20以内的进位加法运算。
教材通过例题和练习，使学生熟练掌握进位加法的运算规律，培养学生的运算能力和逻辑思维能力。
二. 学情分析一年级的学生已经具备了一定的数数能力，对加法运算有一定的认识。
但在实际操作中，可能对进位加法的运算规律还不够熟练，需要通过大量的练习来巩固。
此外，学生的学习兴趣和积极性也需要被激发和保持。
三. 教学目标1.让学生掌握20以内的进位加法运算方法。
2.培养学生的运算能力和逻辑思维能力。
3.激发学生的学习兴趣，提高学生的学习积极性。
四. 教学重难点1.教学重点：让学生掌握进位加法的运算规律。
2.教学难点：如何引导学生理解和掌握进位加法的运算过程。
五. 教学方法采用情景教学法、游戏教学法和小组合作学习法。
通过设定情景，让学生在实际操作中学习进位加法；通过游戏，激发学生的学习兴趣，巩固所学知识；通过小组合作学习，培养学生的团队协作能力和沟通能力。
六. 教学准备1.教学PPT：包括教材中的例题和练习题。
2.教学卡片：用于游戏教学，巩固知识。
3.学习用品：如笔、纸等，供学生练习使用。
七. 教学过程1.导入（5分钟）通过一个简单的加法游戏，引导学生进入学习状态。
例如，教师出示两个数字，让学生快速说出它们的和。
这样的游戏可以激发学生的学习兴趣，同时巩固他们对加法的认识。
2.呈现（10分钟）教师通过PPT呈现教材中的例题，引导学生观察和思考。
例如，出示一个加法算式：3 + 5 = ? 让学生尝试解答。
在学生回答后，教师进行讲解，说明进位加法的运算规律。
3.操练（10分钟）教师让学生进行大量的练习，巩固所学知识。
例如，让学生完成PPT上的练习题，或者发放教学卡片，让学生进行小组内的竞赛。
在学生解答过程中，教师进行巡回指导，帮助学生理解和掌握进位加法的运算过程。
人教版一年级数学上册第八单元教案
人教版一年级数学上册第八单元教案
一、教学目标：
1. 了解数字10及以内的数的读法。
2. 掌握数字10及以内的数的写法及表示方法。
3. 了解数字10及以内的数的奇偶性。
4. 能够在日常生活中熟练运用数字10及以内的数。
二、教学内容：
1. 数字10及以内的读法。
2. 数字10及以内的写法及表示方法。
3. 数字10及以内的奇偶性。
4. 数字10及以内的应用。
三、教学重难点：
1. 数字10及以内的读法。
2. 数字10及以内的奇偶性。
四、教学准备：
1. 数字卡片。
2. 数字棒。
3. 数字贴纸。
4. 运算符号卡片。
五、教学过程：
1. 导入新课：
老师出示数字10及以内的数，让学生大声读出。
2. 分组游戏：
老师将学生分成小组，每组一个贴纸，小组合作，完成数字10及以内的写法及表示方法。
3. 奇偶性探究：
老师用数字棒表示数字10及以内的数，并让学生探究数字的奇偶性。
4. 运算符号练习：
老师出示运算符号卡片，让学生在数字卡片的帮助下，完成简单的加减运算。
5. 运用实践：
老师和学生共同探讨数字10及以内的运用实践，如计数、购物、时间等。
六、教学结束：
1. 对本节课进行总结回顾。
2. 布置数学作业。
七、板书设计：
数字10及以内的读法
数字10及以内的写法及表示方法
数字10及以内的奇偶性
数字10及以内的应用。
一年级上册数学教案第八单元第5课时8、7、6加几(2)人教版
土木工程专业英语翻译土木工程专业外语翻译专业：铁道工程学号：20137084姓名：郭翔西南交通大学峨眉校区2016 年 6 月16 日Building construction concrete crack ofprevention and processingAbstractThe crack problem of concrete is a widespread existence but again difficult in solve of engineering actual problem, this text carried on a study analysis to a little bit familiar crack problem in the concrete engineering, and aim at concrete the circumstance put forward some prevention, processing measure. Keyword:Concrete crack prevention processingForewordConcrete's ising 1 kind is anticipate by the freestone bone, cement, water and other mixture but formation of the in addition material of quality brittleness not and all material.Because the concrete construction transform with oneself, control etc. a series problem, harden model of in the concrete existence numerous tiny hole, spirit cave and tiny crack, is exactly because these beginning start blemish of existence just make the concrete present one some not and all the characteristic of quality.The tiny crack is a kind of harmless crack and accept concrete heavy, defend Shen and a little bit other use function not a creation to endanger.But after the concrete be subjected to lotus carry, difference in temperature etc. function, tiny crack would continuously of expand with connect, end formation we can see without the aid of instruments of macro view the crack be also the crack that the concrete often say in the engineering.Concrete building and Gou piece usually all take sewer to make of, because of crack of existence and development usually make inner part of reinforcing bar etc. material creation decay, lower reinforced concrete material of loading ability, durable and anti- Shen ability, influence building of external appearance, service life, severity will threat arrive people's life and property safety.A lot of all ofcrash of engineerings is because of the unsteady development of the crack with the result that.Modern age science research with a great deal of of the concrete engineering practice certificate, in the concrete engineering crack problem is ineluctable, also acceptable in certainly of the scope just need to adopt valid of measure will it endanger degree control at certain of scope inside.The reinforced concrete norm is also explicit provision:Some structure at place of dissimilarity under the condition allow existence certain the crack of width.But at under construction should as far as possible adopt a valid measure control crack creation, make the structure don't appear crack possibly or as far as possible decrease crack of amount and width, particularly want to as far as possible avoid harmful crack of emergence, insure engineering quality thus.Concrete crack creation of the reason be a lot of and have already transformed to cause of crack:Such as temperature variety, constringency, inflation, the asymmetry sink to sink etc. reason cause of crack;Have outside carry the crack that the function cause;Protected environment not appropriate the crack etc. caused with chemical effect.Want differentiation to treat in the actual engineering, work°out a problem according to the actual circumstance.In the concrete engineering the familiar crack and the prevention1.Stem Suo crack and preventionStem the Suo crack much appear after the concrete protect be over of a period of time or concrete sprinkle to build to complete behind of around a week.In the cement syrup humidity of evaporate would creation stem Suo, and this kind of constringency is can't negative.Stem Suo crack of the creation be main is because of concrete inside outside humidity evaporate degree dissimilarity but cause to transform dissimilarity of result:The concrete is subjected to exterior condition of influence, surface humidity loss lead quick, transform bigger, inner part degree of humidity variety smaller transform smaller, bigger surface stem the Suo transform to be subjected to concrete inner part control, creation more big pull should dint but creation crack.The relative humidity is more low, cement syrup body stem Suo more big, stem the Suo crack be more easy creation.Stemthe Suo crack is much surface parallel lines form or the net shallow thin crack, width many between 0.05-0.2 mm, the flat surface part much see in the big physical volume concrete and follow it more in thinner beam plank short to distribute.Stem Suo crack usually the anti- Shen of influence concrete, cause the durable of the rust eclipse influence concrete of reinforcing bar, under the function of the water pressure dint would creation the water power split crack influence concrete of loading dint etc..Concrete stem the Suo be main with water ash of the concrete ratio, the dosage of the composition, cement of cement, gather to anticipate of the dosage of the property and dosage, in addition etc. relevant. Main prevention measure:While being to choose to use the constringency quantity smaller cement, general low hot water mire and powder ash from stove cement in the adoption, lower the dosage of cement.Two is a concrete of stem the Suo be subjected to water ash ratio of influence more big, water ash ratio more big, stem Suo more big, so in the concrete match the ratio the design should as far as possible control good water ash ratio of choose to use, the Chan add in the meantime accommodation of reduce water.Three is strict control concrete mix blend with under construction of match ratio, use of concrete water quantity absolute can't big in match ratio design give settle of use water quantity.Four is the earlier period which strengthen concrete to protect, and appropriate extension protect of concrete time.Winter construction want to be appropriate extension concrete heat preservation to overlay time, and Tu2 Shua protect to protect.Five is a constitution the accommodation is in the concrete structure of the constringency sew.2.The Su constringency crack and preventionSu constringency is the concrete is before condense, surface because of lose water quicker but creation of constringency.The Su constringency crack is general at dry heat or strong wind the weather appear, crack's much presenting in the center breadth, both ends be in the centerthin and the length be different, with each other not coherent appearance.Shorter crack general long 20-30 cm, the longer crack can reach to a 2-3 m, breadth 1-5 mm.It creation of main reasonis:The concrete is eventually almost having no strength or strength before the Ning very small, perhaps concrete just eventually Ning but strength very hour, be subjected to heat or compare strong wind dint of influence, the concrete surface lose water to lead quick, result in in the capillary creation bigger negative press but make a concrete physical volume sharply constringency, but at this time the strength of concrete again can't resist its constringency, therefore creation cracked.The influence concrete Su constringency open the main factor of crack to have water ash ratio, concrete of condense time, environment temperature, wind velocity, relative humidity...etc..Main prevention measure:One is choose to use stem the Suo value smaller higher Huo sour salt of the earlier period strength or common the Huo sour brine mire.Two is strict the control water ash ratio, the Chan add to efficiently reduce water to increment the collapse of concrete fall a degree and with easy, decrease cement and water of dosage.Three is to sprinkle before building concrete, water basic level and template even to soak through.Four is in time to overlay the perhaps damp grass mat of the plastics thin film, hemp slice etc., keep concrete eventually before the Ning surface is moist, perhaps spray to protect etc. to carry on protect in the concrete surface.Five is in the heat and strong wind the weather to want to establish to hide sun and block breeze facilities, protect in time.3.Sink to sink crack and preventionThe creation which sink to sink crack is because of the structure foundation soil quality not and evenly, loose soft or return to fill soil dishonest or soak in water but result in the asymmetry sink to decline with the result that;Perhaps because of template just degree shortage, the template propped up to once be apart from big or prop up bottom loose move etc. to cause, especially at winter, the template prop up at jelly soil up, jelly the soil turn jelly empress creation asymmetry to sink to decline and cause concrete structure creation crack.This kind crack many is deep enter or pierce through sex crack, it alignment have something to do with sinking to sink a circumstance, general follow with groundperpendicular or present 30 °s-45 ° Cape direction development, bigger sink to sink crack, usually have certain of wrong, crack width usually with sink to decline quantity direct proportion relation.Crack width under the influence of temperature variety smaller.The foundation after transform stability sink to sink crack also basic tend in stability.Main prevention measure:One is rightness loose soft soil, return to fill soil foundation a construction at the upper part structure front should carry on necessity of Hang solid with reinforce.Two is the strength that assurance template is enough and just degree, and prop up firm, and make the foundation be subjected to dint even.Three is keep concrete from sprinkle infusing the foundation in the process is soak by water.Four is time that template tore down to can't be too early, and want to notice to dismantle a mold order of sequence.Five is at jelly soil top take to establish template to notice to adopt certain of prevention measure.4.Temperature crack and preventionTemperature crack much the occurrence is in big surface or difference in temperature variety of the physical volume concrete compare the earth area of the concrete structure.Concrete after sprinkling to build, in the hardening the process, cement water turn a creation a great deal of of water turn hot, .(be the cement dosage is in the 350-550 kg/m 3, each sign square the rice concrete will release a calories of 17500-27500 kJ and make concrete internal thus the temperature rise to reach to 70 ℃or so even higher)Because the physical volume of concrete be more big, a great deal of of water turn hot accumulate at the concrete inner part but not easy send forth, cause inner part the temperature hoick, but the concrete surface spread hot more quick, so formation inside outside of bigger difference in temperature, the bigger difference in temperature result in inner part and exterior hot the degree of the bulge cold Suo dissimilarity, make concrete surface creation certain of pull should dint.When pull should dint exceed the anti- of concrete pull strength extreme limit, concrete surface meeting creation crack, this kind of crack much occurrence after theconcrete under construction period.In the concrete of under construction be difference in temperature variety more big, perhaps is a concrete to be subjected to assault of cold wave etc., will cause concrete surface the temperature sharply descend, but creation constringency, surface constringency of the concrete be subjected to inner part concrete of control, creation very big of pull should dint but creation crack, this kind of crack usually just in more shallow scope of the concrete surface creation.The alignment of the temperature crack usually none settle regulation, big area structure the crack often maneuver interleave;The size bigger structure of the beam plank length, the crack run parallel with short side more;Thorough with pierce through sex of temperature crack general and short side direction parallelism or close parallelism, crack along long side cent the segment appear, in the center more airtight.Crack width the size be different, be subjected to temperature variety influence more obvious, winter compare breadth, summer more narrow.The concrete temperature crack that the heat inflation cause is usually in the center the thick both ends be thin, but cold Suo crack of thick thin variety not too obvious.The emergence of the this kind crack will cause the rust eclipse of reinforcing bar, the carbonization of concrete, the anti- jelly which lower concrete melt, anti- tired and anti- Shen ability etc..Main prevention measure:One is as far as possible choose to use low hot or medium hot water mire, like mineral residue cement, powder ash from stove cement...etc..Two is a decrease cement dosage, cement dosage as far as possible the control is in the 450 kg/m 3 following.Three is to lower water ash ratio, water ash of the general concrete ratio control below 0.6.Four is improvement the bone anticipate class to go together with, the Chan add powder ash from stove or efficiently reduce water etc. to come to reduce cement dosage and lower water to turn hot.Five is an improvement concrete of mix blend to process a craft, lower sprinkle of concrete to build temperature.Six is the in addition that the Chan add a have of fixed amount to reduce water and increase Su, slow Ning etc. function in the concrete, improvement the concrete mix to match a thing of mobility,protect water, lower water to turn hot, postpone hot Feng of emergence time.Seven is the heat season sprinkle to build can the adoption take to establish to hide sun plank etc. assistance measure control concrete of Wen Sheng, lower to sprinkle temperature of build the concrete.Eight is the temperature of big physical volume concrete should the dint relate to structure size, concrete structure size more big, temperature should dint more big, so want reasonable arrangement construction work preface, layering, cent the piece sprinkle to build, for the convenience of in spread hot, let up control.Nine is at great inner part constitution of the physical volume concrete cool off piping, cold water perhaps cold air cool off, let up concrete of inside outside difference in temperature.Ten is the supervision which strengthen concrete temperature, adopt to cool off in time, protection measure.11 is to reserve temperature constringency to sew.12 is to let up to control, sprinkle proper before building concrete in the Ji rock and old concrete top build a 5 mm or so sand mat a layer or usage asphalt etc. material Tu2 Shua.13 is to strengthen concrete to protect, the concrete after sprinkle build use moist grass Lian in time, hemp slice's etc. overlay, and attention sprinkle water to protect, appropriate extension protect time, assurance the concrete surface be slow-moving cool off.At the cold season, concrete surface should constitution heat preservation measure, in order to prevent cold wave assault.14 is the allocation be a little amount in the concrete of reinforcing bar perhaps add fiber material concrete of temperature crack control at certain of scope inside.5.Crack and prevention that the chemical reaction causeAlkali bone's anticipating the crack that reaction crack and reinforcing bar rust eclipse cause is the most familiar in the reinforced concrete structure of because of chemical reaction but cause of crack.The concrete blend a future reunion creation some alkalescence ion, these ion with some activity the bone anticipate creation chemical reaction and absorb surroundings environment in of water but the physical volume enlarge, make concrete crisp loose, inflation open crack.In this kind of crack general emergenceconcrete structure usage period, once appear very difficult remediable, so should at under construction adopt valid the measure carry on prevention.Main of prevention measure:While being to choose to anticipate with the alkali activity small freestone bone.Two is the in addition which choose to use low lye mire with low alkali or have no alkali.Three is the Chan which choose to use accommodation with anticipate to repress an alkali bone to anticipate reaction. Because the concrete sprinkle to build, flap Dao bad perhaps is a reinforcing bar protection layer thinner, the harmful material get into concrete to make reinforcing bar creation rust eclipse, the reinforcing bar physical volume of the rust eclipse inflation, cause concrete bulge crack, the crack of this kind type much is a crack lengthways, follow the position of reinforcing bar ually of prevent measure from have:One is assurance reinforcing bar protection the thickness of the layer.Two is a concrete class to go together with to want good.Three is a concrete to sprinkle to note and flap Dao airtight solid.Four is a reinforcing bar surface layer Tu2 Shua antisepsis coating.Crack processingThe emergence of the crack not only would influence structure of whole with just degree, return will cause the rust eclipse of reinforcing bar, acceleration concrete of carbonization, lower durable and anti- of concrete tired, anti- Shen ability.Therefore according to the property of crack and concrete circumstance we want differentiation to treat, in time processing, with assurance building of safety usage.The repair measure of the concrete crack is main to have the following some method:Surface repair method, infuse syrup, the Qian sew method, the structure reinforce a method, concrete displacement method, electricity chemistry protection method and imitate to living from heal method.Surface repair the method be a kind of simple, familiar of repair method, it main be applicable to stability and to structure loading the ability don't have the surface crack of influence and deep enter crack of processing.The processingmeasure that is usually is a surface in crack daubery cement syrup, the wreath oxygen gum mire or at concrete surface Tu2 Shua paint, asphalt etc. antisepsis material, at protection of in the meantime for keeping concrete from continue under the influence of various function to open crack, usually can adoption the surface in crack glue to stick glass fiber cloth etc. measure.1, infuse syrup, the Qian sew methodInfuse a syrup method main the concrete crack been applicable to have influence or have already defend Shen request to the structure whole of repair, it is make use of pressure equipments gum knot the material press into the crack of concrete, gum knot the material harden behind and concrete formation one be whole, thus reinforce of purpose.The in common use gum knot material has the cement the syrup, epoxy, A Ji C Xi sour ester and gather ammonia ester to equalize to learn material.The Qian sew a method is that the crack be a kind of most in common use method in, it usually is follow the crack dig slot, the Qian fill Su in the slot or rigid water material with attain closing crack of purpose.The in common use Su material has PVC gum mire, plastics ointment, the D Ji rubber etc.;In common use rigid water material is the polymer cement sand syrup.2, the structure reinforce a methodWhen the crack influence arrive concrete structure of function, will consideration adopt to reinforce a method to carry on processing to the concrete structure.The structure reinforce medium in common use main have the following a few method:The piece of enlargement concrete structure in every aspect accumulate, outside the Cape department of the Gou piece pack type steel, adoption prepare should the dint method reinforce, glue to stick steel plate to reinforce, increase to establish fulcrum to reinforce and jet the concrete compensation reinforce.3, concrete displacement methodConcrete displacement method is processing severity damage concrete of a kind of valid method, this method be first will damage of the concrete pick and get ridof, then again displacement go into new of concrete or other material.The in common use displacement material have:Common concrete or the cement sand syrup, polymer or change sex polymer concrete or sand syrup.4, the electricity chemistry protection methodThe electricity chemistry antisepsis is to make use of infliction electric field in lie the quality of electricity chemical effect, change concrete or reinforced concrete the environment appearance of the place, the bluntness turn reinforcing bar to attain the purpose of antisepsis.Cathode protection method, chlorine salt's withdrawing a method, alkalescence to recover a method is a chemistry protection method in three kinds of in common use but valid method.The advantage of this kind of method is a protection method under the influence of environment factor smaller, apply reinforcing bar, concrete of long-term antisepsis, since can used for crack structure already can also used for new set up structure.5, imitate to living from legal moreImitate to living from heal the method be a kind of new crack treatment, its mimicry living creature organization secrete a certain material towards suffering wound part auto, but make the wound part heal of function, join some and special composition(such as contain to glue knot of the liquid Xin fiber or capsule) in the concrete of the tradition the composition, at concrete inner part formation the intelligence type imitate to living from heal nerve network system, be the concrete appear crack secrete a parts of liquid Xin fiber can make the crack re- heal.ConclusionThe crack is widespread in the concrete structure existence of a kind of phenomenon, it of emergence not only will lower the anti- Shen of building ability, influence building of usage function, and will cause the rust eclipse of reinforcing bar, the carbonization of concrete, lower the durable of material, influence building of loading ability, so want to carry on to the concrete crackearnest research, differentiation treat, adoption reasonable of the method carry on processing, and at under construction adopt various valid of prevention measure to prevention crack of emergence and development, assurance building and Gou piece safety, stability work.From《CANADIAN JOURNAL OF CIVIL ENGINEERING》建筑施工混凝土裂缝的预防与处理混凝土的裂缝问题是一个普遍存在而又难于解决的工程实际问题，本文对混凝土工程中常见的一些裂缝问题进行了探讨分析，并针对具体情况提出了一些预防、处理措施。
一年级上册数学教学设计-第八单元《九加几》人教新课标
一年级上册数学教学设计第八单元《九加几》人教新课标我设计的一年级的数学教学，旨在通过第八单元《九加几》的教学，让学生掌握9加几的方法，能正确计算出结果，并在实际情景中应用。
我计划使用人教新课标一年级上册的教材，重点讲解第八单元《九加几》的内容。
这一部分主要包括了9加1到9加9的计算方法，以及如何将这些计算方法应用到实际情景中。
我的教学目标是让学生能够理解9加几的计算方法，并能熟练地运用这种方法进行计算。
同时，我也希望通过这个教学单元，培养学生的逻辑思维能力和解决问题的能力。
在教学过程中，我将会遇到一些难点和重点。
其中难点是如何让学生理解并掌握9加几的计算方法，而重点则是如何引导学生将这种计算方法应用到实际情景中。
为了进行有效的教学，我已经准备了一些教具和学具，包括黑板、粉笔、教学卡片等。
在板书设计上，我会用清晰的文字和图形，展示9加几的计算方法，方便学生理解和记忆。
对于作业设计，我准备了一些相关的题目，如9加1、9加2等，让学生在课后进行练习。
同时，我也准备了一些答案，方便学生自查和巩固所学的内容。
我会进行课后反思和拓展延伸。
我会根据学生的学习情况，调整我的教学方法和策略，以更好地满足学生的学习需求。
同时，我也会寻找一些相关的教学资源，为学生提供更多的学习机会和平台。
重点和难点解析：在上述教学设计中，我认为有几个重点和难点需要特别关注。
重点是让学生理解和掌握9加几的计算方法。
这是整个教学单元的核心，也是学生后续学习更复杂数学知识的基础。
我将通过实际情景的引入和例题的讲解，让学生反复练习，确保他们能够熟练地运用这种方法进行计算。
难点是如何让学生理解并掌握9加几的计算方法。
对于一年级的学生来说，这可能是一个新的概念，他们可能习惯于简单的加法计算，而对于9加几的计算方法可能感到困惑。
因此，我将通过生动的教学卡片和实际操作，让学生在实践中逐步理解和掌握这个方法。
另外，我还将重点关注如何引导学生将9加几的计算方法应用到实际情景中。
一年级上册数学教案-第八单元第五课时解决问题《一共有多少》人教版
一年级上册数学教案第八单元第五课时解决问题《一共有多少》人教版我今天要为大家带来的是人教版一年级上册数学教案中第八单元第五课时的解决问题《一共有多少》。
一、教学内容我们今天要学习的是第八单元的第五课时，主要内容是通过图片和实际情景，让学生理解并掌握“一共有多少”的概念，学会通过数的加法来解决问题。
二、教学目标通过本节课的学习，我希望学生们能够理解“一共有多少”的含义，学会通过数的加法来求解，并能够应用到实际生活中去。
三、教学难点与重点重点是让学生掌握“一共有多少”的概念和求解方法，难点是能够将所学应用到实际情景中。
四、教具与学具准备我准备了一些图片和实物，用于引发学生的兴趣和理解“一共有多少”的概念。
五、教学过程1. 引入：我先拿出一些图片和实物，让学生观察并提问：“这些图片和实物一共有多少个？”引发学生的思考。
2. 讲解：我通过图片和实物，向学生解释“一共有多少”的概念，并引导学生用数的加法来求解。
3. 练习：我给出一些实际情景，让学生练习计算“一共有多少”，如：“我有3个苹果，你给我再拿2个苹果来，一共有多少个苹果？”六、板书设计我在黑板上写下“一共有多少”的板书，并在旁边画上相应的图片和实物，让学生直观地看到求解的过程。
七、作业设计1. 题目：我有5个橘子，你给我再拿3个橘子来，一共有多少个橘子？答案：5 + 3 = 82. 题目：我有7个铅笔，你给我再拿4个铅笔来，一共有多少个铅笔？答案：7 + 4 = 11八、课后反思及拓展延伸通过本节课的学习，我发现学生们对于“一共有多少”的概念和求解方法已经有了初步的理解和掌握，但在实际应用中还需要加强练习。
下一步，我会通过更多的实际情景和练习，让学生们更好地掌握和应用所学知识。
同时，我也会鼓励学生们在日常生活中，多观察、多思考，将所学知识运用到实际生活中去。
重点和难点解析一、引入环节的图片和实物选择在引入环节，我选择了与学生生活密切相关的图片和实物。
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第八单元以内的进位加法
单元教学目标
．使学生比较熟练地口算以内的进位加法。
能正确迅速地进行计算，进一步领会加减法的含义，学会用不同的方法解决生活中的简单问题。
．引导学生经历动手操作、观察、思考，依靠动作和实物思考到脱离实物思考的过程，培养学生的抽象思维能力、语言表达能力、知识迁移能力，获得一些初步的数学活动经验和解决简单问题的方法。
．通过数学学习，使学生初步体验数学及日常生活的密切联系，感受数学在日常生活中的作用，体会学习数学的重要性。
教材说明
本单元学习的主要内容有两个，一是两个一位数相加得数超的加法，简述为“以内的进位加法”；二是“用数学”，即用加法和减法解决简单的问题。
教材内容安排如下表：
以内的进位加法是以内退位减法和多位数计算的基础，这一部分学习的好坏，将对今后计算的正确和迅速程度产生直接的影响。
如果有的学生对这一部分内容没有学好，计算时既慢又容易出错，以后继续学习口算和
多位数笔算时就会遇到很大困难，及其他同学的差距会越来越大。
因此，以内的进位加法也是进一步学习数学必须练好的基本功之一。
用加法和减法解决简单的问题，既有利于学生在用数学中领会加、减法的含义，又可以为以后发现和解决稍复杂的问题打下基础。
本单元计算部分分为三节，即加几，、、加几，、、、加几。
这样编排，体现了学习知识和形成技能的反复认识过程。
并且，每节中内容丰富，比如“、、加几”中含有道加法题。
丰富的教学内容容易引起学生的学习兴趣，也有利于培养学生动脑的习惯。
前两节例题的编排，大体分三个层次：第一，以实际情境提供计算题，并呈现多种计算方法；第二，让学生动手操作或观察，理解和掌握算法；第三，脱离实物，让学生思考算法，算出得数。
这样编排，从学生熟悉的情境出发，提出有关的数学问题，容易激发学生的学习兴趣。
同时，由动手操作、观察，依靠动作和实物思考到脱离实物思考，遵循了由具体到抽象的原则，有利于学生抽象思维能力的培养。
以内进位加法的口算方法不只一种，教材中呈现了多种计算方法，比如在“加几”部分呈现有“点数”、“接着数”、“凑十”和“根据具体题目选择特殊方法”等；在“、、加几”部分呈现有“拆小数，凑十数”、“拆大数，凑小数”和“交换加数的位置”等。
教材注意在具体情景下，让学生自己想出不同的计算方法。
并且，以“你喜欢哪一种方法？”的形式表明允许学生采用不同的方法进行计算的思想，尊重学生的自主选择。
在多种计算方法中，像“点数”和“接着数”等，学生学习在以内计算时已经掌握，因此，不用花很多时间专门进行教学。
“凑十法”是学生新接触的一种方法，掌握起来有一定的难度，所以，教材专门安排例题进
行教学。
“凑十法”是计算进位加法常用的一种方法。
它具有规律性强、易于理解和过程简捷等特点。
并且，在以后学习的计算方法中经常会用到。
掌握好“凑十法”对进一步学习其他计算都有好处。
“凑十法”本身也包括多种方法，如“拆小数，凑大数”和“拆大数，凑小数”等。
其中，“拆小数，凑大数”比较简单，因此，教材先教学这种方法。
在掌握了这种方法的基础上，再教学其他的方法。
这样编排，可以使学生看到，在计算以内的进位加法时，有多种不同的计算方法，他们可以根据题目的具体情况，选择自己喜欢或掌握得比较好的方法进行计算。
从而，更好地发挥学生主动学习的积极性。
在学生理解和掌握算法的基础上，为了使计算达到熟练，教材中适当安排了练习题，并且注意变换练习形式，以提高学生练习的兴趣，使学生通过课堂练习，达到一定的熟练程度。
本单元继续渗透一些集合、函数、统计等数学思想。
如开始讲加几时的例，渗透集合思想；练习十七第题，练习十九第题等渗透函数思想；练习二十一第题，让学生初步接触统计表。
教材中的“用数学”编排在计算当中，比如“加几”中的例及“、、加几”中的例均是“用数学”的内容。
教材中“用数学”的呈现形式是用学生熟悉的事物设计情境图，为学生发现数学问题、探索数学问题提供生动有趣的资源。
本单元“用数学”的内容比第六单元编排的“用数学”画面内容丰富，更注重事理情节。
同时，增加了观察、收集信息的难度，并注意使学生了解同一个问题可以有不同的解决办法。
“用数学”要求学生经历观察发现数学问题，收集解决问题需要的信息、数据，探求解决问题的
方法，求得问题解决的全过程。
实质上是学生运用数学知识的学习活动，对学生体会加、减运算的含义，产生学习数学的兴趣起重要作用。
单元重、难点：熟练掌握自己喜欢的口算方法并能够不明确熟练地算以内的进位加法的口算。
单元课时安排：共课时
（3）怎么解决？
（人）或（人）
教师引导：观察两个算式，它们有什么相同的地方和不同的地方？
小结：解决问题的方法，可能有一种，也可能有多种。
第二关：
一共有几只兔子？
（只）
（只）
第三关：
一共有几只白鹅？最后一关，由孩子们自己提出问题：。