5/4 of a number is 36 less than 4/5 of the same number

First, convert 5/4 to a decimal and 4/5 to a decimal
5/4 = 1.25   and 4/5 =0.8
second, assign variables
the number = x
Write the equation
x(1.25)+36=x(0.8)
SOLVE:
1.25x+36=0.8x
1.25x=0.8x-36
0.45x=-36
x= -80
Check
1.25(-80) +36=0.8(-80)
-64=-64
FINAL ANSWER=
-80