Let's represent the number as x.
According to the given condition, the equation that represents the problem is:
(1/2)x + 26 = 15
Subtract 26 from both sides of the equation:
(1/2)x = 15 - 26
Simplify the right side:
(1/2)x = -11
To solve for x, we need to isolate it on one side of the equation. Multiply both sides by 2:
2(1/2)x = -11 * 2
Simplify:
x = -22
Therefore, the number is -22.