Question

PLEASE HELP 60 POINTS!

Answer 1

Remark
The problem is that she is using the word estimate  (at least in the first two). So put your calculator away and estimate.

Problem One
3 Supreme Pizzas are roughly 17 dollars each which is 51.00
Now we need to look into 4 desert Pizzas which is 4*7 =28.00
The total is 79 dollars. The estimate says she call only afford 3 desert pizzas.
51+21 = 72 dollars roughly, which is not a bad estimate.

Problem Two
The family comes in wanting 1 Supreme at 17.00 + 6 dollars for the cheese sticks. The total is 23 dollars. When you take off the gift certiciate it comes to 23 - 5 = 18 dollars. So the store is correct. It's close enough. 

Comment
The problem is that you are figuring out the exact amount.  One of the most valuable lessons you can learn is how to estimate.  

Problem 3
3 Large Cheese Pizzas are 3 times 15 = 45 dollars.
2 dessert Pizzas come to 2 * 7 = 14 dollars
The total is 59 dollars Estimate for the total is 60 dollars 
20% is about 20/100 = 1/5 of 60 dollars is 12.00
Jacob needs to take this math class if 5 dollars is his answer.

Problem 4
5 supremes are 5 * 17 = 85
5 cheese Pizzas are 5 * 15 = 75
5 Desert Pizzas are 5 * 7 = 35
5 Cheese Sticks = 5 * 6 = 30
Total = 225 You are intended to do this in your head but you can cheat and use  your calculator. Anyway, Jacob redeemed himself. His answer is correct. 

Problem 5
You should estimate it as 
15 dollars for the pizza and 4*1.50 = 15 + 6 = 21.00 It's a bit high. You can do one of two things. You can figure this out exactly or you can drop the number of toppings by one. If you drop by one, you get 19.50 which I don't think an exact answer will improve upon.

In every case, you have not estimated your answer. There are times when exact answers don't give you a quick enough answer.

when you figure our the exact answer for Problem 5 it comes to 20.41. You don't have enough.