Answer:
18+7x=19
Explanation:
18+7x=19
More than in math represents addition, and the "a number" phrase is your variable, which is x.
(this is for if you're supposed to solve the equation)
7x=19-18
7x=1
x=1/7
I'm not really sure if you're supposed to actually solve the problem or write out the equation the question is asking for, but just with the context I'm given hopefully you don't have to) ;D