Réponse :
Explications étape par étape
Bonjour
27 x 101
= 27(100 + 1)
= 2700 + 27
= 2727
57 x 99
= 57(100 - 1)
= 5700 - 57
= 5643
17 x 13
= 17(10 + 3)
= 170 + 51
= 221
45 x 19
= (40 + 5)(20 - 1)
= 40 x 20 - 40 x 1 + 5 x 20 - 5 x 1
= 800 - 40 + 100 - 5
= 900 - 45
= 855
58 x 3 + 58 x 7
= 58(3 + 7)
= 58 x 10
= 580
74 x 1003 - 74 x 3
= 74(1003 - 3)
= 74 x 1000
= 74000
23 x 17 + 23 x 3
= 23(17 + 3)
= 23 x 20
= 460
57 x 107 - 57 x 7
= 57(107 - 7)
= 57 x 100
= 5700
