A. Write true or false .

1. 10 tens make 1 hundred.

2. 100 hundreds make 1 thousand.

3. When there are more than 9 ones, regroup 10 ones into 1 ten.

4. When there are more than 9 tens, regroup 10 hundreds into 1 ten.

5. When there are more than 9 hundreds, regroup 1 hundred into 10 thousands.

B. Fill in the blanks.

1. If you know 3 + 5 = , then you know + 3 = 8.

2. If you know 4 + 0 = , then you know + 4 = 4.

3. If you know 5 + 4 = , then you know + 5 = 9.

4. If you know 6 + 14 = , then you know + 6 = 20.

5. If you know 10 + 30 = , then you know + 10 = 40.

C. Write the following in the columns and add.

1. 1008 + 7944 2. 5167 + 2837 3. 4566 + 2566

4. 1111 + 6652 5. 1121 + 3009