1) 3/7 + 4/9 = 27/63 + 28/63 = 55/632) 8/9 - (-7/8) = 8/9 + 7/8 = 64/72 + 63/72 = 127/723) 13/15 - 2/3 = 26/30 - 20/30 = 6/30 = 1/54) 20/21 + 3/7 = 140/147 + 63/147 = 203/147 = 29/215) 17/18 - 11/12 = 68/72 - 66/72 = 2/72 = 1/366) 7/16 + 1/6 = 21/48 + 8/48 = 29/487) 2/9 + 5/6 = 8/36 + 30/36 = 38/36 = 19/188) 10/21 + 9/14 = 80/168 + 108/168 = 188/168 = 47/429) 7/9 - 4/15 = 35/45 - 12/45 = 23/4510) 9/14 - 3/7 + 15/28 = 36/56 - 24/56 + 30/56 = 42/56 = 3/411) 1/6 + 1/4 - 1/8 = 4/24 + 6/24 - 3/24 = 7/2412) 13/18 - 29/45 + 8/15 = 325/450 - 290/450 + 288/450 = 323/450
1) 3/7 + 4/9 = 27/63 + 28/63 = 55/63
2) 8/9 - (-7/8) = 8/9 + 7/8 = 64/72 + 63/72 = 127/72
3) 13/15 - 2/3 = 26/30 - 20/30 = 6/30 = 1/5
4) 20/21 + 3/7 = 140/147 + 63/147 = 203/147 = 29/21
5) 17/18 - 11/12 = 68/72 - 66/72 = 2/72 = 1/36
6) 7/16 + 1/6 = 21/48 + 8/48 = 29/48
7) 2/9 + 5/6 = 8/36 + 30/36 = 38/36 = 19/18
8) 10/21 + 9/14 = 80/168 + 108/168 = 188/168 = 47/42
9) 7/9 - 4/15 = 35/45 - 12/45 = 23/45
10) 9/14 - 3/7 + 15/28 = 36/56 - 24/56 + 30/56 = 42/56 = 3/4
11) 1/6 + 1/4 - 1/8 = 4/24 + 6/24 - 3/24 = 7/24
12) 13/18 - 29/45 + 8/15 = 325/450 - 290/450 + 288/450 = 323/450