a/b = 5.1
a = 20,4 } => 20,4/b = 5,1 => b = 20,4/5,1 = 4
6 = 2x3
8 = 2³
15 = 3x5
cmmmc = 2³x3x5 = 8x3x5 = 120
a/b = 0,(15) = 15/99
120/b = 15/99
b = 120x99/15
b = 11880/15
b = 792
24 = 2³x3
36 = 2²x3²
60 = 2²x3x5
cmmdc = 2²x3 = 12
a/b = 0,3 = 3/10
12/b = 3/10
b = 12x10/3
b = 120/3
b = 40
