Answer:
x + 5 = 3
Explanation:
"Three is 5 more than a number."
The word is indicates that 3 is the final number, or rather, what the equation equals.
Then, 5 more than a number, shows the rest of your equation. A number is just your variable, so any letter. We'll use X. Then, it says that the answer (3) is 5 more than x. So, your equation is:
x + 5 = 3