Answer:
by adding the 2 to the 8 you get 10 so you just do the same process for 80 and 20 just add the 2 and 8 and then after just add a 0 and there you get the answer 100
Step-by-step explanation:
2+8=10
20+80=100
-1
m=12
21-m=9
-m=9-21
-m=-12
c. $324
15n
3n* 5
