Question

3 tính bằng cách thuận tiện 

25x12x30x4

23+23x2+23x4+23x4

248x2005 - 2005x148

 

 

Answer 1

1/

25x12x30x4

= (25x4)x(12x30)

=100x3600
=360 000

2/

23+23x2+23x3+23x4

=23x1+23x2+23x3+23x4

=23x(1+2+3+4)

=23x10

=230

3/

 248x2005 - 2005x148

=(248-148)x2005

=100x2005

=200500

 

 

Answer 2

1/

25x12x30x4

= (25x4)x(12x30)

=100x3600
=360 000

2/

23+23x2+23x3+23x4

=23x1+23x2+23x3+23x4

=23x(1+2+3+4)

=23x10

=230

3/

 248x2005 - 2005x148

=(248-148)x2005

=100x2005

=200500

Answer 3

1/

25x12x30x4

= (25x4)x(12x30)

=100x3600
=360 000

2/

23+23x2+23x3+23x4

=23x1+23x2+23x3+23x4

=23x(1+2+3+4)

=23x10

=230

3/

 248x2005 - 2005x148

=(248-148)x2005

=100x2005

=200500

Answer 4

a. = ( 25 x 4 ) x ( 12 x 30 ) = 100 x 360 = 36000

b. = 23 x ( 1 + 2 + 4 + 4 ) = 23 x 11 = 253 

c. = 2005 x ( 248 - 148 ) = 2005 x 100 = 200500