А)9/10 * 5/12 б)21/22*2/6 в)3/5*11/5 г)7/8: 7/16 д)1 3/5*2 1/2 е)1 3/4: 10 1/2
#2
а)8/9: 6 в)1: 3/7 д)2 7/9 * 15 б)15*5/6 г)2/5*12 е)3 1/3: 30
#3
а)10: 3 б)42: 8 в)57: 30 г)28: 42

№ 1.

а) 9/10 · 5/12 =(3·1)/(2·4) = 3/8

б) 21/22 · 2/6 = (7·1)/(11·2) = 7/22

в) 3/5 · 11/5 = 33/25 = 1 целая 8/25

г) 7/8 : 7/16 = 7/8 · 16/7 = 16/8 = 2

д) 1 3/5 · 2 1/2 = 8/5 · 5/2 = 8/2 = 4

е) 1 3/4 : 10 1/2 = 7/4 : 21/2 = 7/4 · 2/21 = (1·1)/(2·3) = 1/6

№ 2.

а) 8/9 : 6 = 8/9 · 1/6 = (4·1)/(9·3) = 4/27

б) 15 · 5/6 = (5·5)/2 = 25/2 = 12 целых 1/2

в) 1 : 3/7 = 1 · 7/3 = 7/3 = 2 целых 1/3

г) 2/5 · 12 = 24/5 = 4 целых 4/5

д) 2 7/9 · 15 = 25/9 · 15 = (25·5)/3 = 125/3 = 41 целая 2/3

е) 3 1/3 : 30 = 10/3 · 1/30 = 10/90 = 1/9

№ 3.

а) 10 : 3 = 10/3 = 3 целых 1/3

б) 42 : 8 = 42/8 = 21/4 = 5 целых 1/4

в) 57 : 30 = 57/30 = 19/10 = 1 целая 9/10

г) 28 : 42 = 28/42 = 2/3