b-a=36
a) a=b/2
b-b/2=36
(2b-b)=36x2
b=72
a=72/2=36
72-36=36
b)a=b/3
b-b/3=36
2b=36x3
b=54
a=54/3=18
54-18=36
c)a=b/4
b-b/4=36
3b=36x4
b=144/3=48
a=48/4=12
48-12=36
d)a=b/5
b-b/5=36
4b=36x5
b=180/4=45
a=45/5=9
45-9=36
e) a=b/7
b-b/7=36
6b=36x7
b=252/6=42
a=42/7=6
42-6=36
f)a=b/10
b-b/10=36
9b=36x10
b=360/9=40
a=40/10=4
40-4=36
g)a=b/13
b-b/13=36
12b=36x13
b=468/12=39
a=39/13=3
39-3=36