Răspuns:
a) 20 × 42 × 5 = (20×5) × 42= 100 ×42 = 4200
b) 4 × 28 × 150 = (4×150)× 28= 600 × 28= 16800
c) 4 × 2 × 15 × 5 × 50= (2×50) × (5×4) ×15= 100×20×15=30000
d) 11×322×5 = (5×322)×11= 1610×11= 17 710
e) 250×25×4×2= (25×4)×(250×2)=100 × 500= 50000
f) 500×12×5×2= (500×2)×(12×5)= 1000× 60= 60 000