Hope this will help you. It is a little hard to explain.
Answer:
387
Step-by-step explanation:
Formula: 

Example:
Proportionality=1
5=5x
Divide both sides by 5 , and you get 1=x,
so the proportionality is 1
Answer:
3
Step-by-step explanation:
1. 54÷6 =9
2. (12-4)=8
3. 9-8 = 1
4. 1+2 = 3
5. I hope this helps it's pretty simple oh and 3 is your anansw.Also you can you your calculator