2. Estimation provides a basis for judging whether the results of calculator, oral calculation and written calculation are reasonable. Estimation provides an important basis for judging whether the calculator is accurate, including whether the results of children's oral calculation and written calculation are reasonable. Pupils begin to use calculators, and the calculation results are generally accurate, but sometimes there are problems due to operational errors. If students have the awareness and ability to estimate, they can quickly find out whether the results calculated by the calculator are reasonable or not. In the past, we used the reciprocal relationship of addition and subtraction and the reciprocal relationship of multiplication and division to check, but now we can use estimation to solve it, which is also an important application of estimation.
3. Estimation helps people to grasp the range of operation results in advance, which is an important way to develop students' sense of numbers.
4. Estimation plays an important role in students' subsequent mathematics learning.