Basic Arithmetic and Inverse Operations

The product of two numbers is their result when multiplied. For $3\times 5$, the correct answer is 15.

To find the new score, subtract 45 from 150. The correct result is 105.

To find the total of four copies of 5, you multiply $4\times 5$. Multiplication is the correct operation.

If $84÷7=12$, then to find $12\times 7$, you reverse the division operation. $12\times 7=84$.

To find out how much each person receives, you divide 125 by 5, so each person gets £25.

Subtraction is the inverse operation of addition. So $123456-123456=0$, and the expression simplifies to $5+0=5$.