Pizza perfection sold 93 pizzas on monday, 67 pizzas on tuesday, 78 pizzas on wednesday, 44 pizzas on thursday, and 123 pizzas on friday. on average, how many pizzas did they sell per day?
a. 81
b. 83
c. 82
d. 63

Okay, 
So we know how many pizzas they sold throughout the week, we add those together.
   93
   67
   78
   44
 123
  405

You divide "405" by the amount of numbers there are.

so "5" into "405"
5 goes into 40 8 times
now we have 5 into 5 which goes 1 time.
Our answer is a solid 81.

To check our work, we can multiply 81 by 5. 
5*1=5
5*8=40
405.

A. 81 is your answer