The board is 6 feet long, and there is 12 inches in a foot. This means the board is 72 inches long. Each piece she cuts is 1/4 (3) inches long. This means if we do 72/3, we see the number of pieces Joanna cuts is 24.
(4/7)÷ (3/-8). Division of fractions is the same as multiplying their reciprocals. So (4/7) x (-8/3). Now multiply the numerators together and denominators together (make sure you only use the negative sign once). (4 x -8) / (7 x 3) = -32/21