The number is 15.
Let's solve this problem step-by-step:
Step 1: Define the variable.
Let x be the unknown number.
Step 2: Translate the statement into an equation.
The statement translates to:
"Half of the sum of x and 3 is 9."
We can write this as an equation:
1/2 * (x + 3) = 9
Step 3: Solve the equation for x.
1. Multiply both sides by 2:
(x + 3) = 18
2. Subtract 3 from both sides:
x = 18 - 3
3. Simplify:
x = 15
/--------\
| 9 |
| | Half
| |
+------+------+------+
| x | 3 | |
| | | |
|-------|-------|------|
Number +3 Sum