7 - 6,35= 0,65
0,65 : 6,5 = 0,1
0,1 + 9,9 = 10
1,2 : 36 = 12/360 = 1/30
1,2 : 0.25 = 4,8 = 4 24/30
1/30 + 4 24/30 - 1 5/16 = 4 25/30 -1 5/16 = 4 5/6 - 1 5/16 = 4 40/48 - 1 15/48 =
= 3 25/48 = 169/48
10 : 169/48 = 10 * 48/169 = 480/169
480/169 : 169/24 = 20 !!!