One-to-one method means that all decimals become the smallest integer larger than this decimal.

8.6 - 9

Example:

2.00 1 - 3

9.9 - 10

Generally, one-step method cannot be used in rounding. For example, how many people does it take to move something within a specified time? If the decimal number is calculated, such as 3.2, it is not true, but rounding to 3 is not enough, because it is obviously not enough to need 3.2 people, so it needs 4 people.