Jessie is building a doghouse. for one side of the roof, she needs a board that is 7 3/4 feet long. she has a board that measure 9 1/12 feet. how much of the length does she need to cut from the board? show your work and simply the fraction.

9 1/12 ft = 109/12
7 3/4 = 31/4
You need to give them the same denominator, so you'll need to multiply the top and bottom of 31/4 by three
109/12 - ((31*3)/(4*3))=x
109/12 - 93/12 = x
(109-93)/12 = x
16/12 = x
(16/4)/(12/4) = x
4/3 = x
4/3 = 1 1/3
Jessie needs to cut 1 1/3 feet off the board.