2 целых 4/7 - 1 целое 3/7 +3 целых 1/7 -2 целых 5/7 =..... Срочно !!!
= ( 2(4/7) + 3(1/7) - ( 1(3/7) + 2 (5/7) ) = 5 ( 5/7 ) - 3 (8/7) = 5 (5/7 ) - 4 (1/7) = = 1 ( 4/7 )