Tính. 72 × 30

72 × 30 = ………….

230 × 70 = ………...

63 × 40 = …………..

2 050 × 70 = ……….

85 × 60 = …………

7 400 × 50 = ……..

72 × 30 = (72 × 3) × 10

= 216 × 10

= 2 160

230 × 70

=(23 × 7) × 100

= 161 × 100

= 16 100

63 × 40 = (63 × 4) × 10

= 252 × 10

= 2 520

2 050 × 70

=(205 × 7) × 100

= 1 435 × 100

= 143 500

85 × 60 = (85 × 6) × 10

= 510 × 10

= 5 100

7 400 × 50

=(74 × 5) × 1 000

= 370 × 1 000

= 370 000