(5/6 - 3/7) : 17/21 = 1/2
1) 5/6 - 3/7 = 35/42 - 18/42 = 17/42;
2) 17/42 : 17/21 = 17/42 · 21/17 = 1/2
(5/6 - 3/7) : 17/21 = 1/2
1) 5/6 - 3/7 = 35/42 - 18/42 = 17/42;
2) 17/42 : 17/21 = 17/42 · 21/17 = 1/2