In the teaching of mathematics estimation in the third grade of primary school, it is of positive significance to strengthen students' estimation consciousness and let them master some simple estimation methods, which will help students learn to observe, analyze and solve problems in their daily lives by using mathematical thinking methods, thus cultivating their sense of numbers and their sense of mathematics application.

Estimation method:

1, rounded: 0, 1, 2, 3, 4, none carry, 5, 6, 7, 8, 9, carry.

2. One-to-one method: One-to-one method is to add 1 to the last bit of the reserved part after removing redundant figures. The approximation thus obtained is a residual approximation (i.e., greater than the exact value).

For example, a sack can hold 200 Jin of wheat and there are 880 Jin of wheat. How many sacks do you need to wrap it? When 880 is divided by 200, the quotient is 4, and the remainder is 80, that is, 4 sacks are not enough, and 5 sacks are needed.

3. Truncation method: Truncation method is a commonly used mathematical method, which removes the decimal part of a number and takes its integer part, and its value is approximate (that is, less than the exact value), which is often used in life.

4. Quantity unit estimation method: use real-life objects to perceive the quantity unit and size of actual empirical data.