Bonsoir,
8 x 9 x 10 x 11 x 12 x 13 x 14
= 8 x 9 x (5 x 2) x 11 x (6 x 2) x 13 x (7 x 2)
= 8 x 9 x 5 x 11 x 6 x 13 x 7 x (2 x 2 x 2)
= 8 x 9 x 5 x 11 x 6 x 13 x 7 x 8
= 7 x 9 x 8 x 8 x 5 x 13 x 6 x 11
= (7 x 9) x (8 x 8) x (5 x 13) x (6 x 11)
= 63 x 64 x 65 x 66
