Let us take some example.

1. Let we want to divide 22.5/2.5

  = (225/10)/(25/10)    (Since 22.5 = 225/10 and 2.5 = 25/10)

  =(225*10)/(25*10)

  = 225/25                   (when 10 and 10 is divided by 10)

  = 45/5                       (when 225 and 25 is divided by 5) 

  = 9                            (when 45 is divided by 5)

2. Again Let we have  1.20/4

 = (120/100)/4              (Since 1.20 = 120/100)

= 120/(100*4)

= 120/400

= 12/40             (when 120 and 400 is divided by 10)

= 3/10               (when 12 and 40 is divided by 4)

In this way we devide numbers in decimals and fractions.