# Choosing the Correct Operation

# When to do What

The first step in interpreting word problems is to understand what each of the four basic operations mean. Not knowing HOW to add, subtract, multiply, and divide- rather knowing WHEN.

## STEP 1: WATCH THE VIRTUAL CLASS VIDEO AND TAKE NOTES

### Make sure to note the following:

The four basic operations are addition, subtraction, multiplication and division. It is crucial that you can correctly identify the appropriate operation in the real-world scenarios presented in GED word problems.

Addition: Putting together, or totaling, any sized groups of the same kinds of things. For example: 5 apples and 3 apples equals 8 apples. 5+3=8

Subtraction:

Removing a group from a total. For example: Spending 5 out of 20 dollars leaves you with 15 dollars. 20-5=15

Finding the difference between two numbers. For example: If John is 25 and Marti is 32, Marti is 7 years older than John. 32-25=7

Multiplication:

Putting together same sized groups to find a total. For example: Each student in a GED Class of 15 chips in $5 for pizza for a total of $75. 5(15)=75

Scaling the size of a group. For example: A recipe calls for 4 eggs. John plans to make a half batch, so he only needs 2 eggs. 4(1/2)=2

Division: Breaking a total into same sized groups. For example: A 4 1/2 foot board is sawed into 3/4 foot segments, resulting in 6 segments. 4 1/2 divided by 3/4 = 6

Do you have a question about the class video, practice, or example problems? Post a picture to our FB group for immediate assistance. Be sure to include the lesson name and level in your post.

## STEP 2: COMPLETE ONE LEVEL OF PRACTICE

Practice determining the appropriate operation and writing expressions. See examples #1-5 below.

Use the givens and the appropriate operation to find the indicated information and write an appropriate expression. See examples #4- Challenge #2 below.

Apply the skill of choosing the correct operation to algebra by writing algebraic expressions from word problems. See Challenge #3-5 below.