First you will have to set the equation up like this:
x-1>3+(5-x)
Then solve the equation. First start by turning the x, our variable AKA "a number" as stated in the problem, to a negative this making our equation addition.
x-1>3+5+-x
Then add 3+5 to get 8 to substitute in our equation. after this we can add a positive x to both sides. This will cancel our negative x out, so our variable is on 1 side only,
2x-1>8
Next we can do the same thing again, just with our minus 1.
2x>9
last of all we can divide 2x by two so that we only have x on the left side.
x>4.5
I hope that this helps you! These rule generally apply to most algebraic problems.