Пошаговое объяснение:
1) -1/4+3/5 = -5/20 + 12/20 = 7/20
2) 9/11+(-2/5) = 45/55 - 22/55 = 23/55
3) -20/21+3/7 = -20/21 + 9/21 = -11/21
4) 7 5/12 +(-3 7/24) = 7 10/24 - 3 7/24 = 4 3/24 = 4 1/8
5) -6 11/12 +(-8 13/18) = -6 33/36 - 8 26/36 = -14 59/36 = -15 23/36
6) -5 12/35+1 = -4 12/35
7) -3 1/12+1/6 = -3 1/12 + 2/12 = -2 13/12 + 2/12 = -2 11/12
8) 3 6/7+(-6 4/9) = 3 54/63 - 6 28/63 = 3 54/63 - 5 91/63 = -2 37/63
9) 9 1/6+(-5 3/4) = 9 2/12 - 5 9/12 = 8 14/12 - 5 9/12 = 3 5/12
Пошаговое объяснение:
1) -1/4+3/5 = -5/20 + 12/20 = 7/20
2) 9/11+(-2/5) = 45/55 - 22/55 = 23/55
3) -20/21+3/7 = -20/21 + 9/21 = -11/21
4) 7 5/12 +(-3 7/24) = 7 10/24 - 3 7/24 = 4 3/24 = 4 1/8
5) -6 11/12 +(-8 13/18) = -6 33/36 - 8 26/36 = -14 59/36 = -15 23/36
6) -5 12/35+1 = -4 12/35
7) -3 1/12+1/6 = -3 1/12 + 2/12 = -2 13/12 + 2/12 = -2 11/12
8) 3 6/7+(-6 4/9) = 3 54/63 - 6 28/63 = 3 54/63 - 5 91/63 = -2 37/63
9) 9 1/6+(-5 3/4) = 9 2/12 - 5 9/12 = 8 14/12 - 5 9/12 = 3 5/12