Bonjour,
7/6 ÷ 3/8 = 7/6 × 8/3 = (7×8)/(6×3) = (7×2×4)/(2×3×3) = (7×4)/(3×3) = 28/9
4/21 ÷ 14/9 = 4/21 × 9/14 = (4×9)/(21×14) = (2×2×3×3)/(3×7×2×7)
= (2×3)/(7×7)
= 6/49
18/25 ÷ 6/55 = 18/25 × 55/6 = (18×55)/(25×6)
= (3×6×11×5)/(5×5×6)
= (3×11)/5
= 33/5
8/15 ÷ 1/30 = 8/15 × 30/1 = (8×30)/15 = (8×2×15)/15 = 8×2 = 16
