Réponse :
Bonjour
Explications étape par étape
A = 11/7- 2/5 * 24/7
A = 11/7 - 48/35
A = 55/35 - 48/35
A = 7/35
A = 1/5
A = 0.2
B=3×100000×6×10³÷2×10000000×4,5×10²
B = 3 * 10^5 * 6 * 10^3/2*10^7*4.5*10^2
B = (6*3/2*4.5) * (10^5*10^3/10^7*10^2)
B = 18/9 * [(10^(5+3)/10^(7+2)]
B = 2 * 10^8/10^9
B = 2 * 10^(8-9)
B = 2 * 10^-1
B = 0.2