Answer:
a = 1, b = 2, c = 3
Step-by-step explanation:

1 slice of veggie pizza and 1 slice of pepperoni pizza. = 2 slices of pizza in total
345= 3 hundreds, 4 tens, and 5 ones
391= 3 hundreds, 9 tens, and 1 one
You can use the model I attached to help u see it better.
Hope this helps!
Answer:
9 x 7 = 63 is cost of 9 people
3 x 9
6 x 8
8 x 8
9 x 7