(2- 1 7/12)÷(3/8-1/6)* 3 1/4=

1 12\12 - 1 7\12 = 5\12...................................3\8 - 1\6 = (18 - 8)\48 = 10\48 = 5\24.............................................5\12 : 5\24 =2  2\1 * 13\4 = 13\2 = 6.5   ................................ ответ: 6.5