When asked to add a group of whole numbers, we must recognize and group together the place values of each number.

Let us try 129 + 198 + 321. The solution is (1 + 1 + 3) hundreds, plus (2 + 9 + 2) tens, plus (9 + 8 + 1) ones.

This is simplified as 5 hundreds plus 13 tens plus 18 ones. 13 tens is equal to 1 hundred plus 3 tens. 18 ones is equal to 1 ten plus 8 ones.

The answer is 5 hundreds + 1 hundred, plus 3 tens + 1 ten, plus 8 ones. 6 hundreds plus 4 tens plus 8 ones is simply 648.

Let us try an example where each number has different lengths, such as 2413 + 22 + 917.

Working from right to left, we have (7 + 1 + 3) ones, or 12 ones. We write the 2 and regroup the 1 with the tens. Then we have (1 + 2 + 1) tens, plus the regrouped 1, = 5 tens.

We write the 5 to the left of the 2. Then we have (9 + 4) hundreds, or 13 hundreds.

We write the 3 to the left of the 5 and regroup the 1 with the thousands.

We have 2 plus the regrouped 1, or 3 thousands, so we write the 3 on the left. The answer is 3352.

Let us try 129 + 198 + 321. The solution is (1 + 1 + 3) hundreds, plus (2 + 9 + 2) tens, plus (9 + 8 + 1) ones.

This is simplified as 5 hundreds plus 13 tens plus 18 ones. 13 tens is equal to 1 hundred plus 3 tens. 18 ones is equal to 1 ten plus 8 ones.

The answer is 5 hundreds + 1 hundred, plus 3 tens + 1 ten, plus 8 ones. 6 hundreds plus 4 tens plus 8 ones is simply 648.

Let us try an example where each number has different lengths, such as 2413 + 22 + 917.

Working from right to left, we have (7 + 1 + 3) ones, or 12 ones. We write the 2 and regroup the 1 with the tens. Then we have (1 + 2 + 1) tens, plus the regrouped 1, = 5 tens.

We write the 5 to the left of the 2. Then we have (9 + 4) hundreds, or 13 hundreds.

We write the 3 to the left of the 5 and regroup the 1 with the thousands.

We have 2 plus the regrouped 1, or 3 thousands, so we write the 3 on the left. The answer is 3352.