Bonjour,
On donne: A=2/5 - 1/4 et B=2/3 + 1/6
1) Calculer A et B
A = 2/5 - 1/4
A = (2 x 4) / (5 x 4) - (1 x 5) / (4 x 5)
A = 8/20 - 5/20
A = 3/20
B = 2/3 + 1/6
B = (2 x 2) / (3 x 2) + 1/6
B = 4/6 + 1/6
B = 5/6
2) Calculer A + B
3/20 + 5/6
= (3 x 3) / (20 x 3) + (5 x 10) / (6 x 10)
= 9/60 + 50/60
= 59/60
A-B
3/20 - 5/6
= 9/60 - 50/60
= - 41/60
A/B
3/20 : 5/6
= 3/20 x 6/5
= 18/100
= (2 x 9) / (2 x 50)
= 9/50.
