Word Problems

Turn real-world situations into equations.

What You will learn:

Lesson 1: Translate Words -

keep it simple

“A number plus 7 is 15”
x + 7 = 15

Solve:

1
Subtract 7 from both sides
x + 7 − 7 = 15 − 7
2
x = 8
Check:
8 + 7 = 15

Lesson 2: Set Up the Equation -

one step up

“Twice a number plus 5 is 13”
2x + 5 = 13

Solve:

1
Subtract 5 from both sides
2x + 5 − 5 = 13 − 5
2
2x = 8
3
Divide both sides by 2
2x ÷ 2 = 8 ÷ 2
4
x = 4
Check:
2(4) + 5 = 13

Lesson 3: Solve It -

introduce a real context

“Three times a number minus 4 is 11”
3x − 4 = 11

Solve:

1
Add 4 to both sides
3x − 4 + 4 = 11 + 4
2
3x = 15
3
Divide both sides by 3
3x ÷ 3 = 15 ÷ 3
4
x = 5
Check:
3(5) − 4 = 11
Problem: A phone plan charges a $25 monthly fee plus $0.10 per text message. Last month, Maya's bill was $43. How many text messages did she send?

Step-by-Step Solution:

1
Set up the equation (Let x = texts)
25 + 0.10x = 43
2
Subtract 25 from both sides
0.10x = 43 − 25
3
Result after subtraction
0.10x = 18
4
Divide both sides by 0.10
x = 18 ÷ 0.10
5
x = 180
Final Answer:
Maya sent 180 text messages.

Practice Problems

Easy

Medium

Challenge

Practice Problems

Common Mistakes to Avoid

Quick Recap:

Answer Key:
Easy: 23 − 9 = 14
Medium: 3(5) + 4 = 19
Challenge: 12(9) = 108
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