Bonjour

1)

A = 2/3 + 5/3 x 1/15

A = 2/3 + 5/45

A = (2 x 3) / (3 x 3) + (5 x 1) / (5 x 9)

A = 3/9 + 5/9

A = 8/9

B = (1 - 3/7) : 12/5

B = [(1 x 7) / (1 x 7) - 3/7] : 12/5

B = (7/7 - 3/7) : 12/5

B = 4/7 : 12/5

B = 4/7 x 5/12

B = 20/84

B = (4 x 5) / (4 x 21)

B = 5/21

C = 9/2 : 3

C = 9/2 x 1/3

C = 9/6

C = (3 x 3) / (3 x 2)

C = 3/2

D = (3/4 + 3) : (1/2 + 2)

D = [3/4 + (3 x 4) / (1 x 4)] : [1/2 + (2 x 2) / (1 x 2)]

D = (3/4 + 12/4) : (1/2 + 4/2)

D = 15/4 : 5/2

D = 15/4 x 2/5

D = 30/20

D = (10 x 3) / (10 x 2)

D = 3/2

2)

a. 2/5 + 1

= 2/5 + (1 x 5) / (1 x 5)

= 2/5 + 5/5

= 7/5

b. 3/4 x 2/5

= 6/20

= (2 x 3) / (2 x 10)

= 3/10

c. 1/3 x 2/5 + 2/5

= 2/15 + (2 x 3) / (5 x 3)

= 2/15 + 6/15

= 8/15

d. 3/5 : 2/5

= 3/5 x 5/2

= 15/10

= (5 x 3) / (5 x 2)

= 3/2

e. (3/2 - 10/6) : (2/7 + 1/3)

= [(3 x 3) / (2 x 3) - 10/6] : [(2 x 3) / (7 x 3) + (1 x 7) / (3 x 7)]

= (9/6 - 10/6) : (6/21 + 7/21)

= - 1/6 : 13/21

= - 1/6 x 21/13

= - 21/78

= (3 x - 7) / (3 x 26)

= - 7/26

f. 3 - 5 : (1 + 1/3)

= 3 - 5 : [(1 x 3) / (1 x 3) + 1/3]

= 3 - 5 : (3/3 + 1/3)

= 3 - 5 : 4/3

= 3 - 5 x 3/4

= (3 x 4) / (1 x 4) - 15/4

= 12/4 - 15/4

= - 3/4.