effectuer le calcul ci-dessous et donner le résultat sous forme de fraction iiréductible: A=2/5×[1-(2/3+1/4)]

bonsoir

a = 2/5 x ( 1-(8/12+3/12) )
a = 2/5 x (1 -11/12)
a = 2/5 x (12/12-11/12)
a = 2/5 x 1/12
a = 2 /60
a = 1/30

A = 2/5 x [1 - (2/3 + 1/4)]
A = 2/5 x (1 - 8/12 - 3/12)
A = 2/5 x (12/12 - 11/12)
A = 2/5 x 1/12
A = (2 x 1)/(5 x 12)
A = 2/60
A = 1/30