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2014-03-12T19:45:13+01:00
Va voir le devoir de Elysa41. Les réponses sont bonnes.
c) 13/14+5/7=13/14+10/14=23/14
d) 3/4+5/24=18/24+5/24=23/24
e) 6/7+2/35=30/35+2/35=32/35
f) 11/81+1/9=11/81+99/81=110/81
f)
2014-03-12T20:07:50+01:00

Exercice 33:

a) 1/2 + 1/4 = 1x2/2x2 + 1/4 = 2/4 + 1/4 = 3/4

b) 5/6 + 5/12 = 5x2/6x2 + 5/12 = 10/12 + 5/12 = 15/12 = 5/6

c) 13/14 + 5/7 = 13/14 + 5x2/7x2 = 13/14 + 10/14 = 23/14

d) 3/4 + 5/24 = 3x6/4x6 + 5/24 = 18/24 + 5/24 = 23/24

e) 6/7 + 2/35 = 6x5/7x5 + 2/35 = 30/35 + 2/35 = 32/35

f) 11/81 + 1/9 = 11/81 + 1x9/9x9 = 11/81 + 9/81 = 20/81


Exercice 34:

a) 12/14 - 7/13 = 5/13

b) 1/3 - 1/6 = 1x2/3x2 - 1/6 = 2/6 - 1/6 = 1/6

c) 9/4 - 5/12 = 9x3/4x3 - 5/12 = 27/12 - 5/12 = 22/12 = 11/6

d) 5/6 - 3/48 = 5x8/6x8 - 3/48 = 40/48 - 3/48 = 37/48

e) 9/7 - 64/63 = 9x9/7x9 - 64/63 = 81/63 - 64/63 = 17/63

f) 19/99 - 1/11 = 19/99 - 1x9/11x9 = 19/99 - 9/99 = 10/99 


Exercice 36:

a) 4 - 3/2 = 4x2/1x2 - 3/2 = 8/2 - 3/2 = 5/2

b) 2 - 1/3 = 2x3/1x3 - 1/3 = 6/3 - 1/3 = 5/3

c) 9/4 - 1 = 9/4 - 1x4/1x4 = 9/4 - 4/4 = 5/4

d) 7 + 1/4 = 7x4/1x4 + 1/4 = 28/4 + 1/4 = 29/4

e) 16/3 - 3 = 16/3 - 3x3/1x3 = 16/3 - 9/3 = 7/3

f) 4 + 5/7 = 4x7/1x7 + 5/7 = 28/7 + 5/7 = 33/7

g) 6 - 5/3 - 5/6 = 6x6/1x6 - 5x2/3x2 - 5/6 = 36/6 - 10/6 - 5/6 = 21/6 = 7/2

h) 2 + 3/4 + 7/2 = 2x4/1x4 + 3/4 + 7x2/2x2 = 8/4 + 3/4 + 14/4 = 25/4

i) 7 - 9/5 - 13/25 = 7x25/1x25 - 9x5/5x5 - 13/25 = 175/25 - 45/25 - 13/25 = 117/25