1) (3/8 + 8/21) : 22/66; 8 : 0,4 - 19,36
1. Сложим дроби в скобках: 3/8 + 8/21 = (3*21 + 8*8) / (8*21) = (63 + 64) / 168 = 127 / 168
2. Разделим на 22/66 = 1/3: (127/168) / (1/3) = 127/168 * 3 = 127/56
3. Разделим 8 на 0.4: 8 : 0.4 = 80 : 4 = 20
4. Вычтем: 20 - 19.36 = 0.64
Итого: 127/56 = 2.2678 и 0.64
2) ((15 - 9 2/3) / (19 2/3 - 11 7/9)) : 2/3
1. 15 - 9 2/3 = 15 - 29/3 = 45/3 - 29/3 = 16/3
2. 19 2/3 - 11 7/9 = 59/3 - 106/9 = 177/9 - 106/9 = 71/9
3. (16/3) / (71/9) = (16/3) * (9/71) = 16*3/71 = 48/71
4. (48/71) / (2/3) = (48/71) * (3/2) = 24*3/71 = 72/71
Ответы:
1) 127/56 и 0.64
2) 72/71