Estimation is a necessary computing skill. Learning to estimate can solve practical problems in daily life. Users can first estimate a result when doing a pen calculation, and then compare the result with the estimated result to judge whether the result is correct. It can be said that the application value of estimation is very extensive and can be used at any time.

The estimate is only to find a rough figure, not an accurate result. The method of estimation is to regard multiple numbers as the nearest integer ten, integer hundred and integer thousand, and then multiply them by one number.

Extended data:

Precautions:

The theorem of the special problem in the one-minute quick calculation formula is that the product obtained by multiplying any two digits by any two digits, as long as the Vickers coefficient is 0, must be the product obtained by multiplying the tail in two binomials, and the product obtained by multiplying the head by the head (the sum of one term plus 1) is the previous product and the product obtained by two adjacent terms.

According to the head (one of which adds one) is the front product (the number of adaptive tails is 10), and according to the tail is the back product. The two products are connected and the Wei coefficient can be added to ten digits. ?

Complementarity with the same tail, the first digit is multiplied by a larger number, the product with the mantissa, the tail is complementary to the first digit, the product of the first digit is tailed, and the product with the mantissa.

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