2nd Grade Adding and Subtracting Within 1,000 Quiz: 10 Questions with Explanations

A \(548\)B \(539\)C \(438\)D \(638\)

Adding 100 raises the hundreds digit from 5 to 6. Adding only 10 gives 548, which is a different move.

A \(604\)B \(714\)C \(694\)D \(703\)

704 is 70 tens and 4 ones. One ten less is 69 tens and 4 ones, so 694. Subtracting 100 would give 604.

A \(382\)B \(392\)C \(492\)D \(292\)

Ones: 3 + 9 = 12, so regroup 1 ten. Tens: 5 + 3 + 1 = 9. Hundreds: 2 + 1 = 3. Forgetting to add the regrouped ten gives 382.

A \(337\)B \(463\)C \(437\)D \(347\)

Trade a hundred for 10 tens and then a ten for 10 ones: 5 hundreds, 10 tens, 12 ones. Taking the smaller digit from the larger in each place gives the wrong 463.

A \(285\)B \(675\)C \(295\)D \(385\)

The missing part is 480 – 195 = 285. Adding the two numbers gives 675, which is too big for a part.

A \(200\)B \(290\)C \(299\)D \(310\)

300 is 30 tens. One ten less is 29 tens, which is 290. Subtracting 100 gives 200.

A Write 12 in the ones place.B Write 2 ones and regroup 1 ten.C Write 1 one and regroup 2 tens.D Write 2 ones and regroup 1 hundred.

12 ones are 1 ten and 2 ones. Write the 2 ones and add the 1 ten to the tens column.

A \(699\)B \(790\)C \(889\)D \(789\)

799 – 10 = 789. The tens digit goes down by 1 and the hundreds digit stays 7.

A \(784\)B \(684\)C \(774\)D \(794\)

Ones: 8 + 6 = 14. Tens: 2 + 5 + 1 = 8. Hundreds: 4 + 3 = 7. Forgetting the regrouped ten gives 774.

A \(237 + 723 = 960\)B \(723 + 486 = 1{,}209\)C \(237 + 486 = 723\)D \(486 – 237 = 249\)

Add the difference to the number taken away. 237 + 486 = 723, the starting number.