【正文】 cannot leave the as: 360 present 18 = 360 present nine members present 2 = 40 members present 2 = 20, in the process of the abridged, using three oral such as calculation of 5764 + 3821, and, need four addition oral, any a link error, can lead to , to improve the elementary student39。在教學(xué)中，我每天在課堂上利用35分鐘時間進行口算訓(xùn)練，或視算或聽算，或在作業(yè)中抄一、兩道脫式計算題，每天批閱并及時反饋，逐步提高學(xué)生的計算能力。 ability of calculation.（2）記憶一些常用數(shù)據(jù)和巧算方法。同時，經(jīng)常教學(xué)生一些巧算的方法，也可使其計算速度大大提高。With a number is multiplied by 5, 25, 125, can use opportunely calculate method:245=24247。4100= 324 present 4 x 324 x 324409125=408125+125=408247。Try some division mercial law: differential try to mercial law, with the head in addition to business method(when the Numbers on the dividend and the divisor that high phase at the same time, monly known as the “head”, dividend top is smaller than the divisor, and the divisor and dividend the number of times on the high error is less than the highest level, can be directly used eight and nine test quotient), median try mercial law, binary and mercial law, and so on, these are students quick is necessary to master the basic 、理解算理，提倡算法多樣化要使學(xué)生會算，必須要使其明確算理，這就要求教師對算法和算理的教學(xué)必須正確，因為第一印象非常重要，第一次講錯以后就很難改掉。但如果首次感知不準確，那么造成的不良后果在短期內(nèi)是難以清除的。To make the student union, must make it clear to calculate, this requires teachers to the algorithm and the principle of teaching must be correct, because the first impression is very important, for the first time speak wrong, it is hard to remove it a psychologist said: first perception of new knowledge, proactive inhibition of information into the brain can be affected by the interference, can leave deep impression in students39。算法多樣化不是要求每個學(xué)生都用多種方法解決同一問題，而是要鼓勵學(xué)生獨立思考，用適合自己的方法解決，有能力的可以運用多種方法，沒有這種需求的學(xué)生只用一種即可。特別要對中、高年級提出的每一種算法，可讓其自己說明算理，以防止其“知其然，不知其所以然”，同時起到培養(yǎng)學(xué)生邏輯思維和口頭表達能力的作用。t required that every student(should)use a variety of methods to solve the same problem, but rather to encourage students to think independently and solve with suitable methods, ability can use a variety of methods, without the need of students in a algorithm diversity, also want to pay attention to the optimization method, for students to e up with every kind of right way to give affirmation, persuade students give up their backward trival, to follow the outstanding, simple method, so as to make their thinking ability constantly for middle and senior each kind of algorithm, can calculate, make its own instructions in order to prevent the “l(fā)earning, don39。 logical thinking and the role of oral expression 、重視估算，教給方法Third, the value estimate, teach method在日常生活和生產(chǎn)實際中，某些計算和測量的結(jié)果無法得到或沒有必要得到精確計算結(jié)果或判斷時，就要用到估算的方法。因此，重視學(xué)生估算能力的培養(yǎng)，不僅可以使學(xué)生的思維更加靈活，而且對學(xué)生的直覺思維能力的培養(yǎng)有很大的幫助。在教學(xué)中，我經(jīng)常性地貫穿一些估算的技巧和方法：In our daily life and production practice, some calculation and the measurement result can39。 ability to estimate, therefore, not only can make students39。 ability of intuition thinking has a lot of the same time, strengthen the estimation, can deepen students understanding of digital, promote the cultivation of number sense, enhance the consciousness of applied mathematics, improve the ability of solving practical the teaching, I regularly throughout some estimation techniques and methods:近似估算法。估算過程中，由于學(xué)生的生活背景、思維方式的不同，估算結(jié)果也不一定一樣，因此，允許估算結(jié)果與準確值之間有一定范圍的誤差，正負誤差均可。s life background, the different way of thinking, to estimate the results may not be the same, therefore, allow a certain range between estimation results with the accurate value of error of plus or minus as:783+945≈800+900=1700Material 800 783 + 945 + 900 = 17003927247。40=10003927 present 35 material present 40 4000 = 1000聯(lián)系實際估算法。2, contact the actual as puting, rent a car number, floor number to buy brick, etc., must be an integer, and must adopt “into a”。In addition to classroom teaching methods, the most effective way is to l