1, approximate number, easy to do, easy to find and look at. As soon as you find the horn, you should pay attention to marking it. Second, look at the numbers behind the mark. Four transformers do not input 1, and five transformers input 1.

2. The mantissa length doesn't matter, just look at the highest mantissa. If it is 5, enter 1, otherwise all will be discarded.

3. Before rounding the decimal, add 4 to the maximum value and add 5 to the bottom by subtracting 1.

4. Keep looking at the next position, it is 5 big 5 forward 1, and remove all less than 5; The last step must not be forgotten, the equal sign is replaced by the equal sign.

5, keep accurate and get, approximate rounding.

6. The digital difference is 1, with a maximum of four rooms and a minimum of five rooms; The digit difference of 2 is greater than 2, the maximum value is 4 shekels and the minimum value is 5 shekels.

7, the rounding method is good, the approximate number can be found, which one to look at the next position, and then compare five words, that is, 5 big 5 forward 1, less than 5 completely abandoned, equal sign replaced by equal sign, so that people can understand at a glance.

Approximation is a number that is close to an exact number by rounding. The "0" at the end of the divisor cannot be discarded casually. Rounding is the most commonly used method to find approximate values. When the highest digit of the omitted mantissa is 4 or less, the mantissa is truncated; When the number on the highest digit of the omitted mantissa is 5 or more, it needs to go forward 1 after the mantissa is removed.