§ 5. Звичайні дроби » 1073

Обчисліть суму: 1) 3/7 + 2 = (3/7 + 7/7) + 1 = 1 + 10/7 = 110/7 = 23/7 2) 21/5 + 4/5 = 2 + (1/5 + 4/5) = 2 + 5/5 = 3 3) 24/9 + 52/9 = (2 + 5) + (4/9 + 2/9) = 76/9 4) 46/11 + 27/11 = (4 + 2) + (6/11 + 7/11) = 613/11 = 72/11 5) 11/7 + 32/7 + 23/7 = (1 + 3 + 2) + (1/7 + 2/7 + 3/7) = 6 + 6/7 = 66/7 6) 31/8 + 23/8 + 7/8 = (3 + 2) + (1/8 + 3/8 + 7/8) = 511/8 = 63/8