1, tail removal method. That is, the mantissa of each number is removed and the whole number is calculated.

2, into the law. That is, the highest digit of each number plus 1 is calculated as an integer of ten.

3. Rounding method. That is, mantissa is less than or equal to 4, mantissa is equal to or greater than 5, and it is calculated by integer ten or integer hundred.

4. Ten methods add up. That is, the related figures add up to close to 10.

5. Find the whole by parts, divide a large whole into several parts on average, and find the integer according to the number of parts.

6. The actual estimate is based on certain standards. One is to estimate by counting units, the other is to estimate by measuring units, and the third is to estimate by taking an object as a reference.

7, rounding method, the number as an algebraic expression, in the calculation of the whole 100 thousand, is the most commonly used estimation method.

It is estimated that the Chinese word pinyin is ɡū suàn, which means approximate calculation. Such as estimate production.

In psychology, estimation is a general inference or estimation of the number of things or the result of formulas according to specific conditions and related knowledge. In mathematics, estimation is an important part of computing power.

The role of evaluation

1 helps students to improve their judgment and choice ability.

2. It is beneficial to cultivate students' planning.

3. Estimation plays an important role in students' subsequent mathematics learning.

The commonly used estimation methods are as follows:

1, rounding method: for example, one thousand, one hundred and ten.

2. Take an intermediate number, such as 53, 57, 5 1 and 59. These figures are very close to 35, some are a little more than 55, and some are a little less than 55. Take an intermediate number 55, and directly use 55×4 to roughly calculate the addition result of these numbers.

3. Use special data features to estimate numbers: for example, 126 × 8, we can think of 125 × 8 and 125 as 8 times, and get 1000.

4. Size coordination: two numbers, one is estimated to be larger, the other is estimated to be smaller, or the other is not estimated.