Second, to approximate, it is generally necessary to keep the corresponding digits as required; If there is no such requirement in the title, there can be different results. For example,

3. 198475≈3 (reserved integer),

Note: "Keep integer" can also be said to be "accurate to one place"-when the number on the tenth place is 4 or less, the number on the tenth place or less is directly removed (rounded); When the number at the tenth place is 5 or more, the number after the tenth place is removed, and 1 (in) is added to the unit number. The tenth point of this problem is that 1 should be "discarded".

3. 198475=3.2 (keep one decimal place),

Note: "Keep one decimal place" can also be said to be "accurate to ten places". The number in the percentile of this question is 9, which should be "in".

3. 198475=3.20 (two decimal places are reserved),

Note: "Keep two decimal places" can also be said to be "accurate to 1%". The number on one thousandth of this question is 8, which should be "into".

34588≈34590 (whole ten digits reserved),

34588≈34600 (keep the whole hundred numbers),

34588≈35000 (keep whole thousand)

Besides rounding, there are other ways to get approximate values, such as rounding (whatever the next digit is, it is left) and closing (whatever the next digit is, it is in). When there is no special explanation, the approximate method should be determined according to the actual situation.

For example, when you make a product and ask how many pieces you can make, you should use the tail cutting method; When figuring out how much materials are needed, we should use the closing method (this is to ensure that the materials are enough).

The number of digits that should be reserved for approximation sometimes depends on the actual situation, such as the number of people and the number of articles. , the integer should be kept; Find the amount of RMB (unit: yuan), and generally keep two decimal places.