a) 80 × (70 + 190) = 80 × 70 + 80 × 190
b) 900 × 700 × 600 = 900 × 600 × 700
= 700 × 900 × 60p
c) 40 × 901 + 60 × 901 + 50 × 901 = 150 × 901
