Réponse:
a= 1/14 - 5×2/7×2 = 1/14 - 10/14 = -9/14
b= -7×10/10×10 + -5/100 = -70/100 + -5/100 = -75/100
c= -6/1 - 1/3 = -6×3/1×3 - 1/3 = -18/3 - 1/3 = -19/3
d= -1×3/4×3 - 8/12 = -3/12-8/12 = -11/12
e= 4/15+ -7×5/3×5 = 4/15 + -35/15 = -31/15
f= 13/12 - -5×2/6×2 = 13/12 - -10/12 = 23/12
voilà!!