Halfway Between 3 and 21

When you ask "What number is halfway between 3 and 21?" we assume you mean the number in the exact middle of the two numbers on a number line, as illustrated below, where X=3 and Y=21.

Halfway Between Line

To find the number halfway between 3 and 21, we use the following formula:

(X + Y)/2 = Halfway Between

When we enter 3 and 21 into our formula, we get:

(3 + 21)/2 = 12

Thus, the number halfway between 3 and 21 is 12.

To check that our answer is correct, we subtract 3 from 12 and subtract 12 from 21 and compare the two numbers:

12 - 3 = 9
21 - 12 = 9

As you can see, the halfway number is 9 higher than 3 and 9 lower than 21. Therefore, our halfway between answer of 12 above is correct.

Halfway Between
Find halfway between two other numbers here!

Halfway Between 3 and 22
Here is our next Halfway Between calculation.