Subtraction — Practice Quiz

168

Step 1: Pinky had 316, gave away 148. We need 316 - 148. Step 2: Ones: 6 - 8, since 6 < 8, borrow 1 ten. 1 ten becomes 0 tens, 6 ones becomes 16 ones. Step 3: 16 - 8 = 8 ones. Step 4: Tens: 0 - 4, since 0 < 4, borrow 1 hundred. 3 hundreds becomes 2 hundreds, 0 tens becomes 10 tens. Step 5: 10 - 4 = 6 tens. Hundreds: 2 - 1 = 1. Answer is 168.

97

Step 1: We need 105 - 8. Step 2: Ones: 5 - 8, since 5 < 8, we need to borrow. There are 0 tens, so borrow from hundreds. 1 hundred becomes 0 hundreds, 0 tens becomes 10 tens. Step 3: Borrow 1 ten for ones. 10 tens becomes 9 tens, 5 ones becomes 15 ones. Step 4: 15 - 8 = 7 ones. Tens: 9 (nothing to subtract). Hundreds: 0. Answer is 97.

86 - 72

Step 1: Calculate all four differences. Step 2: 99 - 66 = 33. Step 3: 78 - 35 = 43. Step 4: 57 - 36 = 21. Step 5: 86 - 72 = 14. Comparing: 14 < 21 < 33 < 43. So 86 - 72 = 14 is the smallest answer.

487

Step 1: Total seats = 644, passengers seated = 157. We need 644 - 157. Step 2: Ones: 4 - 7, since 4 < 7, borrow 1 ten. 4 tens becomes 3 tens, 4 ones becomes 14 ones. Step 3: 14 - 7 = 7 ones. Step 4: Tens: 3 - 5, since 3 < 5, borrow 1 hundred. 6 hundreds becomes 5 hundreds, 3 tens becomes 13 tens. Step 5: 13 - 5 = 8 tens. Hundreds: 5 - 1 = 4. Answer is 487.