What is 983 minus 909?

• A. 70
• B. 74
• C. 75
• D. 78

Answer: (B)

Subtracting with place-value borrowing is the trick here. Align the numbers by their digits and look at each place value from right to left. In the ones place, you can’t do 3 minus 9, so you borrow 1 from the tens. That makes the ones digit 13 minus 9, which equals 4, and reduces the tens digit from 8 to 7. Now the tens place is 7 minus 0, which gives 7. The hundreds place is 9 minus 9, which is 0. Put the digits together and you get 0 for the hundreds, 7 for the tens, and 4 for the ones, i.e., 74. The borrowing step is what makes the ones place become 4 and the tens place become 7, yielding the correct result.