## Periodic Cost

A periodic cost is something you pay for over and over again instead of just once. This is for things like a water bill or a magazine subscription. Usually you pay either once per month or once per year.
It can be useful to convert between a monthly cost and a yearly cost to compare two periodic costs. For example, a magazine subscription is \$10 per month. To calculate how much you would pay every year, do the following:
```monthly cost = \$10
yearly cost  = \$10 × 12 = \$120
```
Now let's say that magazine subscription is \$90 per year. To calculate how much you would pay every month, do the following:
```yearly cost  = \$90
monthly cost = \$90 ÷ 12 = \$7.50
```

### Exercise 1 of 6

An internet provider is \$50 per month. How much would you pay every year?

### Exercise 2 of 6

A cell phone plan is \$40 per month. How much would you pay every year?

### Exercise 3 of 6

A car insurance policy is \$945 per year. This is called the premium, and is what consumers pay to the insurance company. In exchange, the insurance company pays for costs that are covered under the policy. How much would you pay every month? In the address bar, use / to divide.

### Exercise 4 of 6

A home insurance policy is \$1,383 per year. How much would you pay every month?

### Exercise 5 of 6

A video streaming service is \$14 per month, but you can get a yearly plan for \$140. How much would you save per year with the yearly plan?

### Exercise 6 of 6

A gym membership is \$10 per month, but you can get a yearly membership for \$99. How much would you save per month with the yearly membership?