【文章內(nèi)容簡介】 hase 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。記得一位心理學家說過：首次感知新知識時，進入大腦的信息可以有受前攝抑制的干擾，能在學生的大腦皮層留下深刻的印象。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。因此，教師必須充分備課，選擇最優(yōu)方案，以期達到良好的教學效果。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。 brain if the first perception is not accurate, the adverse consequences in the short term is difficult to , the teacher must fully preparation, select the optimal scheme, in order to achieve good teaching ，要提倡算法多樣化。算法多樣化不是要求每個學生都用多種方法解決同一問題，而是要鼓勵學生獨立思考，用適合自己的方法解決，有能力的可以運用多種方法，沒有這種需求的學生只用一種即可。提倡算法多樣化，也要注意方法的優(yōu)化，對于學生想出的每一種正確方法都給予肯定，說服學生放棄自己的落后繁瑣觀點，去遵循優(yōu)秀、簡潔的方法，這樣才能使自己的思維能力不斷提高。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)學生邏輯思維和口頭表達能力的作用。In students is clear, on the basis of to promote diversity algorithm isn39。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。t know why”, at the same time cultivate students39。 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。如一個房間的大小、從家到學校的距離、某樓房的高度、有經(jīng)驗有漁民判斷某片水域里魚的數(shù)量等。因此，重視學生估算能力的培養(yǎng)，不僅可以使學生的思維更加靈活，而且對學生的直覺思維能力的培養(yǎng)有很大的幫助。同時，加強估算，可以加深學生對數(shù)字的認識，促進數(shù)感的培養(yǎng)，增強應用數(shù)學的意識，提高解決實際問題的能力。在教學中，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。t get or there is no need to get the precise result or judgment, is employed to estimate as the size of a room, the distance from home to school, a building height, experienced fishermen who judge a number of fish in the water, to the cultivation of students39。 ability to estimate, therefore, not only can make students39。 thinking more flexible, but also for the cultivation of the 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。在實際計算中，根據(jù)情況把兩個數(shù)同時估大或同時估小，或一個估大一個估小，以便口算為宜。估算過程中，由于學生的生活背景、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。如：1, the approximate the actual calculation, according to the number two at the same time for large or for small at the same time, or a big one for small forecast, so that verbal arithmetic is process, because the student39。s life background, the different way of thinking, to estimate the results may not be the same, th