【文章內(nèi)容簡介】 用到估算的方法。如一個房間的大小、從家到學(xué)校的距離、某樓房的高度、有經(jīng)驗(yàn)有漁民判斷某片水域里魚的數(shù)量等。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。同時，加強(qiáng)估算，可以加深學(xué)生對數(shù)字的認(rèn)識，促進(jìn)數(shù)感的培養(yǎng)，增強(qiáng)應(yīng)用數(shù)學(xué)的意識，提高解決實(shí)際問題的能力。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。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(shí)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(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(zhǔn)確值之間有一定范圍的誤差，正負(fù)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, 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。35≈4000247。40=10003927 present 35 material present 40 4000 = 1000聯(lián)系實(shí)際估算法。如計算人數(shù)、租車數(shù)量、鋪地買磚等，都必須是整數(shù)，且得采用“進(jìn)一法”；用鐵皮做鐵盒，鐵盒必須是整數(shù)，且得使用“去尾法”。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”。Do with tin tin box, tin box must be an integer, and must use the “method” to ，最有效的方法是讓學(xué)生在實(shí)際生活中鍛煉，在處理具體問題中提高。In addition to classroom teaching methods, the most effective way is to let students exercise in real life, in dealing with specific 、增強(qiáng)學(xué)生的實(shí)踐能力數(shù)學(xué)來源于生活，又服務(wù)于生活，而計算則是解決實(shí)際生活問題的重要手段。Mathematics es from life and serves life, and the calculation is the important means to solve the problem of real 、呈現(xiàn)方式生活化?！缎抡n標(biāo)》中指出：要通過現(xiàn)實(shí)生活的情境，使學(xué)生體驗(yàn)、感受和理解數(shù)與運(yùn)算的意義，要呈現(xiàn)給學(xué)生大量的現(xiàn)實(shí)背景，從中體會數(shù)學(xué)與生活的密切聯(lián)系。如在教學(xué)364時，我以如下方式導(dǎo)入：一件上衣36元錢，買4件這樣的上衣需要多少錢？這種賦計算式題予生活的方法，學(xué)生非常樂于接受。1, the present way of life.“New standard” pointed out: through to real life situations, make students experience, feel and understand the meaning of number and operations, to be presented to students a lot of realistic background, closely related to mathematics and the in teaching 36 x 4, I import in the following way: a top 36 yuan, how much do you need to buy 4 such blouse? This way of life for the calculation type questions, students are willing to 、日常生活數(shù)學(xué)化。生活中處處有數(shù)學(xué)，如上街購買衣物，大約需要帶多少錢，需要估算；準(zhǔn)備購買多少件物品，也需要統(tǒng)計和計算，所以，要教育學(xué)生留意身邊數(shù)學(xué)。在隨家長買菜時，要特別留心售貨員是如何快速算出結(jié)果的。同時，也要用所學(xué)過的估算、巧算等方法幫著大人算一算，以提高自己的計算能力。2, daily life in the life mathematics, such as street to buy clothes, about how much money need to take, need to estimate。Ready to buy how many pieces of goods, also need to statistics and putation, so paying conscious attention to mathematics education to along with the parents to buy food, pay special attention salesman is how to quickly calculate the learned at the same time, also want to use the methods of estimation, qiao is help to calculate a calculate, in order to improve their puting 、養(yǎng)成教育不容忽視良好的習(xí)慣，直接影響著計算的速度和準(zhǔn)確率。在教學(xué)中，我發(fā)現(xiàn)學(xué)生計算題出錯的原因并不是不會做，而是不用心，所以我認(rèn)為要讓學(xué)生養(yǎng)成如下良好習(xí)慣。Good habits and directly affects the calculation speed and the teaching, I found that students39。 math error reasons not to do, but not by heart, so I think to make students form good habits as 、規(guī)范書寫。由于書寫不規(guī)范而造成計算錯誤的現(xiàn)象屢見不鮮，如由于把“5”連筆寫，計算下一步時就誤看成了“8”；把“7”潦草地寫成了“1”，而造成計算結(jié)果錯誤。教師要嚴(yán)格要求學(xué)生的書寫格式，并以身作則，當(dāng)好榜樣。1, written in the error caused by writing is not standard phenomenon, such as due to the “5” cursive writing, when calculating the next step is mistakenly identified as “8”。Write a “7” scrawled “1”, and cause calcu