1-1) 25/100 = 25/(4*25) = 1/4
1-2) 75/125 = (3*25)/(5*25) = 3/5
1-3) 108/144 = (4*27)/(4*36) = 27/36
2-1) (3*11)/(11*21) = 3 / (7*3) = 1/7
2-2) (15*3) / (12*25) = (5*3*3) / (3*4*5*5) = 3 / (4*5) = 3/20
