846 найдите значение выражения
8:2 2/5. 2 1/7:5/7
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5 1/4:7. 4:8/9

8 : 2 2/5 = 8/1 • 5/12 = 10/3;5 1/4 : 7 = 21/4 • 1/7 = 3/4;10/3 : 3/4 = 10/3 • 4/3 = 40/9;2 1/7 : 5/7 = 15/7 • 7/5 = 3;4 : 8/9 = 4 • 9/8 = 9/2;3 : 9/2 = 3 • 2/9 = 2/3;40/9 : 2/3 = 40/9 • 3/2 = 20/3 = 6 2/3