2. Найдите значение выражения: a) 7 - 4 5/9; б) 4 3/10 + 1 1/2; в) 6 15/21 + 2 9/14; г) 5 1/6 - 3 3/4.

a) 7 - 4 5/9 = 6 9/9 - 4 5/9 = (6 - 4) + (9/9 - 5/9) = 2 4/9 б) 4 3/10 + 1 1/2 = 4 3/10 + 1 5/10 = (4 + 1) + (3/10 + 5/10) = 5 8/10 = 5 4/5 в) 6 15/21 + 2 9/14 = 6 (15*2)/(21*2) + 2 (9*3)/(14*3) = 6 30/42 + 2 27/42 = (6+2) + (30/42 + 27/42) = 8 + 57/42 = 8 + 1 15/42 = 9 15/42 = 9 5/14 г) 5 1/6 - 3 3/4 = 5 2/12 - 3 9/12 = 4 14/12 - 3 9/12 = (4-3) + (14/12 - 9/12) = 1 5/12 Ответ: a) 2 4/9; б) 5 4/5; в) 9 5/14; г) 1 5/12