Question

Please help me i need this really bad

Answer 1

It's 3!

Explanation:

3 books times 6 dollars each = 18 dollars.

21 minus 18 dollars = 3.

Answer 2

The answer is 3
Multiply 6 by 3 to get the total amount of money for the books then minus the answer 18 which you get from 6 x 3 = 18
Then minus 18 from 21 to get $3
21 - 18 = 3