Answer:
12
Step-by-step explanation:
84-54=30
30/2.5=12
Answer:
Step-by-step explanation:
You can perform all kind of operation that are one the inverse of the other, so that the value won't change. For example, you can multiply and divide by 2:

Or add and subtract 5:

Answer:
30
Step-by-step explanation:
9 + 13 = 22
22 + 43 = 65
65 + 55 = 120
120 ÷ 4 = 30
hope this helps