Solve an algebraic equation with one variable

Objectives
Student will be able to:
  • solve addition and subtraction equations containing one variable.
  • use inverse operations to isolate the variable in an equation.
  • check solutions to addition and subtraction equations with one variable.

Exercises
Complete the exercises. Check solutions.
1.
The difference between a certain number and 38 is 25. What is the number?
 
 
 
 The number is 63.
 
1.
 

2.
Serena finds that 20 plus a certain number equals 45. What is the number?
 
 
 The number is 25.
 
2.
 

3.
Jonathan is 45 years old. He is 20 years younger than Mr. Davis. How old is Mr. Davis?
 
 
 Mr. Davis is 65 years old.
 
3.
 

4.
Janine bought a jacket for $83. This is $49 more than Kiara paid for the same jacket on sale. What sale price did Kiara pay?
 
 
 Kiara paid $34 to buy the jacket on sale.
 
4.
 

5.
Thirty years ago, Mr. Sawyer bought a house that was 26 years old. How old is his house now?
 
 His house is 56 years old.
 
5.
 

6.
Randy scored 20 points playing basketball. This was 11 points more than he scored in the last game. How many points did Randy score in the last game?
 
 Randy scored 9 points in the last game.
 
6.