Answer: 8
Step-by-step explanation:
First, we will write a mathematical expression to represent the given sentence. "The sum" means addition and "is" means equals. Let x be equal to "a number" in this case.
4 + x + 5 = 17
Next, combine like terms.
9 + x = 17
Lastly, subtract 9 from both sides of the equation:
x = 8
The number is 8.
