Bonjour
Calculer en simplifiant si possible et vérifier avec la calculatrice
A= 2/7-3/7×14/9
A = (2 x 9) / (7 x 9) - 42/63
A = 18/63 - 42/63
A = - 24/63
A = (3 x - 8) / (3 x 21)
A = - 8/21.
B= -7/8×(2/3-1)
B = - 7/5 x [2/3 - (1 x 3) / (1 x 3)]
B = - 7/5 x (2/3 - 3/3)
B = - 7/5 x (- 1/3)
B = 21/15
B = (3 x 7) / (3 x 5)
B = 7/5
C=4/5×1/4+2/5
C = 4/20 + (2 x 4) / (5 x 4)
C = 4/20 + 8/20
C = 12/20
C = (4 x 3) / (4 x 5)
C = 3/5.
