Use the commutative and associative properties of addition to find the sum. See Example.45...

Use the commutative and associative properties of addition to find the sum. See Example.

457 + 97 + 653

Example

Add:

a. 3 + 5 + 17 + 2 + 3

b.

Strategy We will look for groups of two (or three numbers) whose sum is 10 or 20 or 30, and so on.

WHY This method is easier than adding unrelated numbers, and it reduces the chances of a mistake.

Solution

Together, the commutative and associative properties of addition enable us to use any order or grouping to add whole numbers.

a. We will write the steps of the solution in horizontal form.

b. Each step of the addition is explained separately. Your solution should look like the last step.

The sum is 1,117.