Question

Tính bằng cách thuận tiện:

a) 2019 x 2 x 5

b) 5 x 8 x 9 x 2 x 125

c) 4 x 2019 x 25

d) 50 x 125 x 2 x 8 x 202

Answer 1

a, 2019 x (2 x 5)

= 2019 x 10

= 20 190

 

b, (5 x 2) x (8 x 125) x 9

= 10 x 1000 x 9

= 90 000

 

c, (4 x 25) x 2019

= 100 x 2019

= 201 900

 

d, (50 x 2) x (125 x 8) x 202

= 100 x 1000 x 202

= 20 200 000

Answer 2

a) 2019 x 2 x 5

= (2 x 5) x 2019

= 10 x 2019

= 20190

b) 5 x 8 x 9 x 2 x 125

= (5 x 2) x (125 x 8) x 9

= 10 x 1000 x 9

= 10000 x 9

= 90000

c) 4 x 2019 x 25

= (4 x 25) x 2019

= 100 x 2019

= 201900

d) 50 x 125 x 2 x 8 x 202

= (50 x 2) x (125 x 8) x 202

= 100 x 1000 x 202

= 100000 x 202

= 20200000