Seven more than one number equals nine less than double that number. Find that number.

That number is 16

Explanation:
Step 1 - Write down the information you know

*ps. for this problem we will be using x to represent the unknown number. for future problems, just know that unless a variable has an assigned letter to represent it, you can usually pick whichever letter you’d like

• “Seven more” — “7 +”
• “then one number equals” — “x =”
• “nine less than” — “- 9”
• “double that number” — “2x”

Step 2 - Write an equation using the information you know

x + 7 = 2x - 9

Step 3 - Subtract x from both sides of the equation

x + 7 = 2x - 9
x - x + 7 = 2x - x - 9
7 = x - 9

Step 4 - Add 9 to both sides of he equation and then switch sides

7 = x - 9
7 + 9 = x - 9 + 9
16 = x
x = 16

Now that we have found the value of x, we know that the number is 16.

The first option would be correct if it were one half and not one