4/9:16/45= 6 10/13:1 5/39=. 55:11/12=
4/9 : 16/45 = 4*45 /9 *16 =5/4=1 1/4 6 10/13 : 1 5/39 = 88 *39 /13 *44=6 55 : 11/12 =55 *12 /11=5*12=60