Answer:
-5.25 + 3.5 = -1.75
Step-by-step explanation:
This can technically be done two ways. The first is the most simplified, and the second less simplified, and less likely to get the best grade.
1.So long as you don't have to order it chronologically, you should be good with this one: 
2.This one IS chronological (she got a correct answer, then a wrong answer), but you can NOT simplify it, because it asks for an addition equation: 
The best option is probably #1
80 km
You do 240/60 which is 4 and then times that by 20. By dividing 240 by 60 you are finding how far it goes per minute and then you times that by how many minutes(20) which is 80 km
18/4.50 because you want to find out how many you can buy you divide your answer is 4