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?
Step-by-step reasoning:
8
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.

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Thus, the answer is 8