(6 5/9 - 3 1/4)*2 2/17=
(6 5/9 - 3 1/4) * 2 2/17 = (59/9 - 13/4 ) * 36/17 = (236/36 - 117/36) * 36/17 = 119/36 *36/17 = 7
Спасибо