А) 37,5 -(62,01 -15,7) + (-37,5 +62,01 -30,3) = 37,5-62,01 +15,7 -37,5 +62,01 +30,3 = 15,7 +30,3 =46,0
б) (7 4/21 - 3 9/21 ) - (1 5/28 - 3 10/21) = 3 16/21 - ( 1 15/84 - 3 40/84) =
3 16/21 - ( - 2 25/84) = 3 16/21 + 2 25/84 = 3 64/84 + 2 25/84 = 5 89/84 = 6 5/84