N 1 а) 1 1/5 + 3/10 = 1 + (1/5 + 3/10) = 1 +(2/10 + 3/10 ) = 1 + 5/10 = 1 1/2
б) 3 3/5 - 2,6 = 18/5 - 26/10 = 36/10 - 26/10 = 10/10 = 1
в) 1 1/2 * 2 2/9 = 3/2 * 20/9 = 10/3 = 3 1/3
г) 2 5/8 / 3 1/16 = 21/8 / 49/16 = 6/7
№ 2 . Ответ в двух цистернах бензина : (7 5/8) * 2 - 1 = 14 10/8 - 1 = 14 2/8 = 14 1/4 тонна
№3 а) х + 5 7/24 = 6 5/12
х = 6 5/12 - 5 7/24 = (6 - 5) + (5/12 - 7/24) = 1 + (10/24 - 7/24) = 1 + 3/24 = 1 3/24 = 1 1/8
б) 2 3/5 - у = 0,6
13/5 - 6/10 = у
у = 26/10 - 6/10
у = 20/10 = 2
№4 а) 0,6 + 2 3/4 + 0,6 * 7 1/4 = 0,6(2 3/4 + 7 1/4) = 0,6 * 10 = 6
б) 7 5/6 * 6/13 - 6/13 * 5 2/3 = 6/13 (7 5/6 - 5 2/3) = 6/13((7 - 5)+ (5/6 - 2/3)) =
6/13(2 +(5/6 - 4/6)) = 6/13(2 + 1/6) = 6/13 * 2 1/6 = 6/13 * 13/6 = 1