Question: I caught 4 fewer fish than the number in my tank and added them to my fish tank. If the tank has 20 fish right now, how many did I add?
Solution:
Let's say the number of fish that was in the tank before was x
If you caught 4 fewer fish than the number that was there, then you caught x-4
After adding x-4 fish into the tank, the tank now had 20 fish, meaning the total number of fish in the tank is x+x-4=20
2x=20+4
The total number of fish that was initially in the tank is 2x=24
Initially, there were x=24/2 fish in the tank
x=12
If you caught 4 fewer fish than the number in my tank initially, you caught 12-4=8 fish.
Answer: 8