Question

Tính hợp lí

19.25-(-19).75

(-25).(75-45)-75.(45-25)

Answer 1

19.25-(-19).75

= 19.25-19.(-75)

= 19 . [ 25-( -75 ) ]

=19.100 = 1900

Answer 2

19.25-(-19).75

= 19.25 +19,75

= 19(25+75)

=19 .100

= 1900

Answer 3

(-25).(75-45)-75.(45-25)

= (-25).(75-45) - [(-25).(75-45).-2]

=-750-(-750).-2

= -2250

Answer 4

(-25).(75-45)-75.(45-25)

= -25 . 75 - ( -25) .45 - 75 .45 - 75.25

= -25.75 + 25.45 -75.45 - 75.25

= 75. ( -25+25) - 45. ( 25-75)

= 45. (-50)

= -2250

Answer 5

19 . 25 - (-19) .75

= 19 . 25 - {(-19) . ( -1)} . { 75 . ( -1)}

= 19 . 25 - 19 . ( -75)

= 19 . { 25 - ( - 75)}

= 19 . 100

= 1900

( -25) . (75-45) -75. ( 45 - 25)

= ( -25) . 30 - 75 .20

= -750 - 1500

= -2250