One-step method is to add 1 to the last bit of the reserved part after removing the 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? Divide 880 by 200 to get 4.4. If rounded, it is 4. But it is impossible to pack in four sacks, and only one method can be used, five sacks.