Change 53% to a decimal. Doing so, we get 0.53.
Let n = the number we are looking for.
The word "is" in math means to use the equal sign.
135 = 0.53n
Divide both sides by 0.53.
135/0.53 = 0.53n/0.53
254.7169811321 = n
Rounding to the nearest tenths, we get
n = 254.72
Done!