Subtract the difference between the total length of the board (8 feet) and 7 feet 10 3/4 inches. To make it easier, convert both measurements to inches.
1 foot= 12 inches
TOTAL LENGTH: multiply total length by number of inches in 1 foot. 8 feet * 12 inches= 96 inches
LENGTH TO BE CUT: 7 feet * 12 inches=84 inches 84 + 10 3/4 inches= 94 3/4= 94.75
FIND DIFFERENCE: =96 - 94.75 =1.25 inches =1 1/4 inch