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
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