(7 - 3 7/11) - (4 - 3/11) = - 4/11
1) 7 - 3 7/11 = 6 11/11 - 3 7/11 = 3 4/11
2) 4 - 3/11 = 3 11/11 - 3/11 = 3 8/11
3) 3 4/11 - 3 8/11 = - (3 8/11 - 3 4/11) = - 4/11
(8 - 4 13/20) - (96 - 5 3/20) = - 87 1/2
1) 8 - 4 13/20 = 7 20/20 - 4 13/20 = 3 7/20
2) 96 - 5 3/20 = 95 20/20 - 5 3/20 = 90 17/20
3) 3 7/20 - 90 17/20 = - (90 17/20 - 3 7/20) = - 87 10/20 = - 87 1/2