Final answer:
The magician has 8 non-normal fair coins, calculated by subtracting the 12 normal fair coins from the total of 20 coins.
Step-by-step explanation:
The student's question asks how many of the magician's coins are not normal fair coins, given that out of 20 coins, 12 are normal fair coins. The remaining coins can be found by subtracting the number of fair coins from the total number of coins.
Number of coins that are not normal fair = Total number of coins - Number of normal fair coins
Calculation:
Number of coins that are not normal fair = 20 coins - 12 coins = 8 coins.
Therefore, the magician has 8 non-normal fair coins.