Вычисли: а) -2,5 - ( - 1 2/3 + 2 1/3) б) 3 2/19 - ( - 7/19 - 1 1/2)

а) -2,5 - (-1 2/3 + 2 1/3) = -2,5 - (-5/3 + 7/3) = -2,5 - 2/3 = -7,5/3 - 2/3 = -9,5/3 = -3 0,5/3;

б) 3 2/19 - (-7/19 - 1 1/2) = 59/19 - (-7/19 - 3/2) = 59/19 - (-14/38 - 57/38) = 59/19 - (-71/38) = 

= 59/19 + 71/38 = 118/38 + 71/38 = 189/38 = 4 37/38.