Question

You have a piece of wood that is 7 3/4 feet long.  You want to cut one piece that is 3 7/12 feet long and one piece that is 4 1/12 feet long.  Do  you have enough wood? Explain.

Answer 1

$7 \frac{3}{4} - (3 \frac{7}{12} + 4 \frac{1}{12} ) = 7 \frac{3}{4} - 7 \frac{8}{12} = 7 \frac{9}{12} - 7 \frac{8}{12} = \frac{1}{12}$

yeah , enough ...

Answer 2

$3\frac7{12}+4\frac1{12}=7\frac8{12}\\ \\ 7\frac34=7\frac9{12}\\\\ 7\frac8{12}$