а) 2/3 + 1/5 = 10/15 + 3/15 = 13/15б) 3/8 + 5/12 = 9/24 + 10/24 = 19/24в) 3/14 + 2/21 - 9/35 = 45/630 + 40/630 - 162/630 = -77/630г) 3/10 + 1/8 - 2/5 = 24/80 + 10/80 - 32/80 = 2/80 = 1/40
а) 2/3 + 1/5 = 10/15 + 3/15 = 13/15
б) 3/8 + 5/12 = 9/24 + 10/24 = 19/24
в) 3/14 + 2/21 - 9/35 = 45/630 + 40/630 - 162/630 = -77/630
г) 3/10 + 1/8 - 2/5 = 24/80 + 10/80 - 32/80 = 2/80 = 1/40