Bonjour
9)
a. 43/10 + 5/10 = 48/10 = (2 x 24) / (2 x 5) = 24/5
b. 6/12 + 2/24 = 6/12 + (2 x 1) / (2 x 12) = 6/12 + 1/12 = 7/12
c. 6/5 + 2/15 = (6 x 3) / (5 x 3) + 2/15 = 18/15 + 2/15 = 20/15 = (5 x 4) / (5 x 3) = 4/3
d. 1/30 + 2/3 = 1/30 + (2 x 10) / (3 x 10) = 1/30 + 20/30 = 21/30 = (3 x 7) / (3 x 10) = 7/10
10)
a. 5/6 + 7/18 = (5 x 3) / (6 x 3) + 7/18 = 15/18 + 7/18 = 22/18 = (2 x 11) / (2 x 9) = 11/9
b. 7/3 - 1/12 = (7 x 4) / (3 x 4) - 1/12 = 28/12 - 1/12 = 27/12 = (3 x 9) / (3 x 4) = 9/4
c. 11/20 + 3/4 = 11/20 + (3 x 5) / (4 x 5) = 11/20 + 15/20 = 26/20 = (2 x 13) / (2 x 10) = 13/10
d. 23/18 - 8/18 = 15/18 = (3 x 5) / (3x 6) = 5/6.
