Tính bằng cách thuận tiện. a) 2 136 × 5 × 2 b) 5 × 2 × 33 613 c) 2 × 392 × 5 d) 5 × 3 598 × 2

a) 2 136 × 5 × 2 = 2 136 × (5 × 2) = 2 136 × 10 = 21 360

b) 5 × 2 × 33 613 = (5 × 2) × 33 613 = 10 × 33 613 = 336 130

c) 2 × 392 × 5 = (2 × 5) × 392 = 10 × 392 = 3 920

d) 5 × 3 598 × 2 = 3 598 × (5 × 2) = 3 598 × 10 = 35 980