If the sum of two numbers is 30 and one of them is 12, what is the other number?

To find the other number when the sum of two numbers is given, you can use a simple algebraic approach. The problem states that the sum of two numbers is 30, and one of those numbers is 12.

You can express this mathematically as:

[ x + 12 = 30 ]

In this equation, ( x ) represents the other number. To solve for ( x ), subtract 12 from both sides:

[ x = 30 - 12 ]

Calculating this gives:

[ x = 18 ]

Thus, the other number must be 18. This aligns with the first step of isolating the other number by subtracting the known number from the total sum.

This approach confirms that the correct answer is indeed 18.