Question

2Tính nhanh:

a) 152. 19 + 152. 81                                      b) 197. 50 – 50. 98 + 50

b) 1000 + (–470 ) + 3215 +(–530)                   c) – 479 – ( 2002 – 479 ) 

Answer 1

a) 152. 19 + 152. 81 

= 152.( 19+ 81 )

= 152. 100

= 15200  

b) 197. 50 – 50. 98 + 50

= 50.( 197 - 98 + 1)

= 50. 100

= 5000

 b) 1000 + (–470 ) + 3215 +(–530)    

= 1000 + [(–470 ) + (–530)]  + 3215

= 1000  + (-1000) + 3215

= 0 + 3215 

= 3215 

c) – 479 – ( 2002 – 479 ) 

=  – 479  - 2002 + 479

= [(– 479 + 479)] –  2002

= 0 - 2002 

= -2002

 

 

 

Answer 2

2Tính nhanh:

a) 152. 19 + 152. 81                                    b) 197. 50 – 50. 98 + 50

=152.(19+81)                                                =50.(197-98)+50                                          

=152.100                                                       =50.99+50

=1520                                                             =5000

b) 1000 + (–470 ) + 3215 +(–530)                   c) – 479 – ( 2002 – 479 ) 

=1000+[ (–470 )+ (–530) ]+ 3215               =-479+2002+479

=1000+(-1000)+3215                                =(-479+479)+2002

=0+3215                                                    =0+2002

=3215                                                        =2002