6 2/3 - ( x + 1/4) = 2 1/6

1/4=0.25
62/3 - x - 0,25 = 21/6
62/3 - 0,25 - 21/6= x
62/3 - 1/4 - 21/6 = x
248-3-42/12= x
203/12=x

6 2/3 - ( х + 1/4 ) = 2 1/6
6 8/24 - ( х + 6/24) = 2 4/24
х + 6/24 = 6 8/24 - 2 4/24
х + 6/24 = 4 4/24
х = 4 4/24 - 6/24
х = 3 28/24 - 6/24
х = 3 22/24