Question

What is 54/100 ins simplest form and 72/100, 90/100?

Answer 1

Do you still want it as a fraction or a decimal?
 If you want it as a fraction:
54/100= 27/50
72/100=36/50=18/25
90/100=45/50
In decimals:
54/100=0.54
72/100=0.72
90/100=0.90

Answer 2

In 54/100, 2 is the only common factor.  Dividing 54 and 100 both by 2, we get 27/50.  This is the simplest form of 54/100.  Note that 54/100=0.54.

In 90/100, 10 is the only common factor.  Divide both 90 and 100 by 10.  We get 9/10.  That's the simplest form.