What is the inverse operation of subtraction?

If x + 2 = 12 , what is the first step to solve for x?

If x - 7 = -4 , what is the first step to solve for x?

Solve

3 + x = 21

What is the inverse operation of division?

Solve

x - 3 = 12

Solve

5x = 95

What is the inverse operation of addition?

Solve

-5 + x = 50

$$18=\frac{a}{2}$$  

$$\frac{r}{3}=7$$  

$$\frac{v}{5}=9$$  

Shana bought a hamburger for $4.25, two hot dogs for $2.50 each, a large order of fries for $2.95, and one medium soda for $2.15. If Shana paid with a $20.00 bill, how much change did she receive?

Mr. Parker had $86 to buy school supplies for his class. He bought 32 boxes of pencils and 32 packages of notebook paper. Each package of paper cost $1.09, and each box of pencils cost $0.75. How much money did Mr. Parker have left?

There are 20 cars in a parking lot.

Geico provides insurance to 3/5 of the cars.

AllState provides insurance to one-tenth of the cars.

State Farm provides insurance to the remaining cars.

How many cars in this parking lot does State Farm provide insurance to?

Carlos uses a cleaner after working in his garage. The bottle contains 64.2 mL of cleaner. He used 5.8 mL of the cleaner on Monday. On Tuesday, he used half of the remaining cleaner on a chemical spill. On Wednesday, he used 3.9 mL of the cleaner in the bottle. How many mL of cleaner did Carlos have left on Thursday?

Marvin had 2 spools of thread. Each spool contained $$10\ \frac{1}{2}$$    yards of thread. Marvin used 4 yards from each spool. How many yards of thread did Marvin have left?

Angelo has $5.50 for lunch. He buys a cookie for $1.05 and a drink for 1.45. How much money does Angelo have left?

Nik brought a bag of candy to school. He started with 50 pieces, but gave out 15 pieces to EACH of his TWO friends. His nice math teacher gave Nik 3 pieces of candy. How much does he have now?