Bonjour
1/4+7/8
= (1 x 2)/(4 x 2) + 7/8
= 2/8 + 7/8
= (2 + 7)/8
= 9/8
1/5+2/15+3/10
= (1 x 6)/(5 x 6) + (2 x 2)/(15 x 2) + (3 x 3)/(10 x 3)
= 6/30 + 4/30 + 9/30
= (6 + 4 + 9)/30
= 19/30
2/7+5/21+3/14
= (2 x 2)/(7 x 2) + 5/21 + 3/14
= 4/14 + 3/14 + 5/21
= 7/14 + 5/21
= (7 x 3)/(14 x 3) + (5 x 2)/(21 x 2)
= 21/42 + 10/42
= 31/42
5/9+1/3+1/5
= 5/9 + (1 x 3)/(3 x 3) + 1/5
= 5/9 + 3/9 + 1/5
= 8/9 + 1/5
= (8 x 5)/(9 x 5) + (1 x 9)/(5 x 9)
= 40/45 + 9/45
= 49/45
5/6+2/3+5/12
= (5 x 2)/(6 x 2) + (2 x 4)/(3 x 4) + 5/12
= 10/12 + 8/12 + 5/12
= 23/12
3+4/5
= (3 x 5)/5 + 4/5
= 15/5 + 4/5
= 19/5
7+(2/3x1/2)
= 7 + (2 x 1)/(3 x 2)
= 7 + 1/3
= (7 x 3)/3 + 1/3
= 21/3 + 1/3
= 22/3
3/2(1/2+1/3)
= 3/2[(1 x 3)/(2 x 3) + (1 x 2)/(3 x 2)]
= 3/2(3/6 + 2/6)
= 3/2 x 5/6
= (3 x 5)/(2 x 6)
= 5/(2 x 2)
= 5/4
2(1/4+1/3)
= 2[(1 x 3)/(4 x 3) + (1 x 4)/(3 x 4)]
= 2(3/12 + 4/12)
= 2 x 7/12
= (2 x 7)/(2 x 6)
= 7/6
(1/3+1/2)(1/3+1/2)
= (1/3 + 1/2)^2
= (1/3)^2 + 2 x 1/3 x 1/2 + (1/2)^2
= 1/9 + 1/3 + 1/4
= (1 x 4)/(9 x 4) + (1 x 12)/(3 x 12) + (1 x 9)/(4 x 9)
= 4/36 + 12/36 + 9/36
= 25/36
