Réponse :

Explications étape par étape

Bonsoir

Determiner l'écriture simplifier de l'expression: 1+1sur2+1sur3+1sur4+1sur5+1sur6+1sur7

= 1 + 1/2 + 1/3 + 1/4 + 1/5 + 1/6 + 1/7

= 6/6 + 3/6 + 2/6 + 5/20 + 4/20 + 1/6 + 1/7

= 12/6 + 9/20 + 1/7

= 2 + 9/20 + 1/7

= 40/20 + 9/20 + 20/140

= 49/20 + 20/140

= 343/140 + 20/140

= 363/140

1 + 1/2 = 3/2

3/2 + 1/3 = 11/6

11/6 + 1/4 = 22/12 + 3/12 =25/12

25/12 + 1/5 = 125/60 + 12/60 = 137/60

137/60 + 1/6 =  137/60 + 10/60 = 147/60 = 49/20

49/20 + 1/7 = 343/140 + 20/140 = 363/140