2-5 Addition and Subtraction Equations

Important points to remember:

1.) Use the opposite operation to solve

2.) What you do to one side of the equation you must do to the other side of the equation

3.) Always check your answer

Two ways to show your work. Use the horizontal method for number 1 and 2.

1.) m + 4 = 15 2.) w - 7 = 24

Use the vertical method for number 3 and 4.

3.) y + 345 = 567 4.) p - 45 = 238

Rewrite the problem so there is only one sign in numbers 5 and 6.

5.) c + (-4) = -5 6.) w - (-3) = -9

Sometimes it is easier to change the order of the problem. Rewrite the problem

in numbers 7-9 so the variable is first and the answer is last. 7.) -12 + w = 15 8.) -49 = b 12

9.) -10 + x = -2    10.) a 7 = -32

Word Problems

Steps:1.) Identify what the variable represents2.) Write and solve the equation.3.) Write your answer in a sentence

1.) Susan's math teacher assigned x homework problems on Monday. On Tuesday, she assigned 15 problems. Over the two days, a total of 24 homework problems were assigned. Write an equation and solve the equation to find the number of problems she assigned on Monday.

2.)You pay $1.70 for a box of oatmeal after using a coupon for $.80 off. Find the regular price of the oatmeal.

Demonstrate Understanding: Solve each11.) q 15 = -27   12.) x + (-4) = 29

13.) w (-19) = -8  14.) 29 + y = -36

15.) -17 + w = 7   16.) -14 + a = -2

17.) y + (-34) = -4  18.) p 15 = -7

19.) -r + 12 = 5 20.) w + (-18) = -2  

 

21.) There are 160 players in a soccer league. This is 23 more than last year. Find the number of players that were in the soccer league last year.

22.) You spend $12.75 at the movie theater. You purchase a ticket, a container ofpopcorn for $3.25, and a bottle of water for $2. How much does the movieticket cost?

Steps:1.) Identify what the variable represents2.) Write and solve the equation.3.) Write your answer in a sentence