Пошаговое объяснение:

№1

а)

1) (3/5)² * 1 2/3 = 9/25 * 5/3 = 3/5 * 1/1 = 3/5

2) 3/5 + 12 2/9 = 27/45 + 12 10/45 = 12 37/45

б)

1) 13 4/5 * 1 7/23 = 69/5 * 30/23 = 3/1 * 6/1 = 18/1 = 18

2) 18 - (3/4)² = 18 - 9/16 = 17 16/16 - 9/16 = 17 7/16

в)

1) 11 1/4 - 8 4/5 = 11 5/20 - 8 16/20 = 10 25/20 - 8 16/20 = 2 9/20

2) 2 9/20 * (3/7)² = 49/20 * 9/49 = 1/20 * 9/1 = 9/20

№2

1) 6/7 * 140 = 6/1 * 20 = 120/1 = 120 (грн) - стоимость блокнота

2) 5/6 * 120 = 5/1 * 20 = 100/1 = 100 (грн) - стоимость тетради