bjr

207 x 11

= 207 x (10 + 1)

= 207 x 10 + 207 x +1

= 2070 + 207

= 2277

473 x 101

= 473 x (100 + 1)

= 473 x 100 + 473 x 1

= 47300 + 473

= 47 773

et 15 x 99

= 15 x (100 - 1)

= 15 x 100 - 15 x 1

tu peux finir