2. Difference: When intercepting the divisor, the one-by-one method must advance one place regardless of the highest digit of the omitted part. The approximate value obtained by one-step method is greater than the exact number; Rounding means that when intercepting the divisor, no matter what the highest digit of the omitted part is, all the divisors obtained by rounding are discarded, and the divisors obtained by rounding are less than the exact number.