Although the estimate is an estimate, there is nothing to guess. The evaluation strategies are flexible and diverse. The answer is generally not unique. But the estimate is not irregular. There are general rules.

In the specific estimation process,? There are several evaluation strategies:

( 1)? The method of rounding. For example, estimate 182×58. It is generally considered to be 200×60. It can also be regarded as180× 60; ?

(2) Take a middle number. For example, when the four numbers 32, 37, 30 and 39 are added together, they are all close to 35, some are a little more than 35, and some are a little less than 35. Just take an intermediate number 35 and directly use 35×4 to calculate the result of adding these numbers.

(3) Use special data features to estimate the quantity. If 126×8, we can think of 125×8 and get1000;

(4) Find the interval. In other words, the scope of finding it, also known as "going from tail to tail" and "going from tail to tail", means only looking at the first place, and the estimated result is the least. "One is the first plus one. If we say 278, we will take it as 300, and the first place plus one is what it may be at most, so that we can get an interval, which is its interval range;

(5) Two numbers, one estimated in most parts, one estimated in a small part, or one estimated and one not estimated.

(6) Estimate first and then adjust.