Пошаговое объяснение:
Вариант 1
а) 1 1/6 * 1 5/7 = 7/6 * 12/7 = 1/1 * 2/1 = 2/1 = 2
б) 9 3/8 * 2 2/5 = 75/8 * 12/5 = 15/2 * 3/1 = 45/2 = 22 1/2
в)
1) 3 3/11 * 1 2/9 = 36/11 * 11/9 = 4/1 * 1/1 = 4/1 = 4
2) 4 - 2 3/8 = 3 8/8 - 2 3/8 = 1 5/8
3) 1 5/8 * 16/39 = 13/8 * 16/39 = 1/1 * 2/3 = 2/3
Вариант 2
а) 4 1/6 * 2 2/5 = 25/6 * 12/5 = 5/1 * 2/1 = 10/1 = 10
б) 2 1/10 * 2 1/7 = 21/10 * 15/7 = 3/2 * 3/1 = 9/2 = 4 1/2
в)
1) 4 1/12 * 1 5/7 = 49/12 * 12/7 = 7/1 * 1/1 = 7/1 = 7
2) 7 - 5 2/9 = 6 9/9 - 5 2/9 = 1 7/9
3) 1 7/9 * 3/8 = 16/9 * 3/8 = 2/3 * 1/1 = 2/3
4х - мама
4х+х=80
5х=80
х=80/5
х=16сл. - отгадала Даша
16*4=64сл. - отгадала мама