Question

Tính hợp lí

a) 1050:15-150:15+150:19+1940

b)53*39+47*39-53*21-47*21

c)2*53*12+4*6*87

Answer 1

a)1050 : 15 - 150 : 15 + 150 : 19 + 1940

=(1050 : 15 +1940) +(-150 : 15 + 150 :19 )

=(1050 : 15 +29100 : 15) - 150 : ( 15 -19 )

=(1050 + 29100) : 15 - 150 :(-4)

=30150 :15 +37,5

=2010 +37,5

=2047,5

b)53.39 + 47.39 - 53.21 - 47.21

=39(53 + 47) - 21(53 + 47)

=100(39-21)

=100.18

=1800

c)2.53.12 + 4.6.87

=24.53 + 24.87

=24(53 + 87)

=24.140

=3360

Answer 2

a)1050 : 15 - 150 : 15 + 150 : 19 + 1940

= (1050 : 15 +1940) +(-150 : 15 + 150 :19 )

= (1050 : 15 +29100 : 15) - 150 : ( 15 -19 )

= (1050 + 29100) : 15 - 150 :(-4)

=30150 :15 +37,5

=2010 +37,5

=2047,5

Answer 3

b) 53.39 + 47.39 - 53.21 - 47.21

= 39.(53 + 47) - 21(53 + 47)

= 100.(39-21)

=100.18

=1800

Answer 4

c)2.53.12 + 4.6.87

=24.53 + 24.87

=24(53 + 87)

=24.140

=3360