Помогите вычислить:

1-1/2=

1-1/3=

1-2/3=

1-1/4=

8/18-8/27=

7/16-5/24=

2/11-1/12=

а) 1-1/2 = 2/2/1/2=1/2

б) 1-1/3=3/3-1/3=2/3

в) 1-2/3=3/3-2/3=1/3

г) 1-1/4=4/4-1/4=3/4

д) 8/18-8/27=4/9-8/27 = (4*3) / (9*3) - 8/27=12/27-8/27=4/27

е) 7/16-5/24 = (7*3) / (16*3) - (5*2) / (24*2) = 21/48-10/48=11/48

ж) 2/11-1/12 = (2*12) / (11*12) - (1*11) / (12*11) = 24/132-11/132=13/132