dễ mà : a, 5 - ( 1997 - 2005 ) +1997
= ( 2005 + 5 ) - ( 1997 - 1997 )
= 2010 - 0
= 2010
a, 5 - (1997 -2005 ) + 1997
= 5 - 1997 + 2005 +1997
= (5 + 2005 ) - ( 1997 - 1997)
= 2010 - 0
= 2010
b, 4567 + (1234 - 4567 )-4
= 4567 + 1234 - 4567 -4
= (4567 - 4567 ) + (1234 - 4)
= 0 + 1230
= 1230
c, 173 - ( 36 + 173 ) + [(175 - 27 ) - 175 - ( -36 + 50 )]
= 173 - 36 - 173 + 175 - 27 - 175 - 36 - 50
= ( 173 - 173 ) + (175 - 175 ) - ( 36 + 36 ) - (27 + 50)
= 72 - 77
= -5
d, 3 . (25 : 5 - 14 : 2 ) - 5 . ( 6 : 2)
= 3 (-2) - 5 .3
= 3 ( -2 - 5 )
= 3 . (-7 )
= - 21
a) 5-(1997-2005)+1997
= 5-(-1997)+2005+1997
= (5+2005)+(-1997+1997)
= 2010+0
= 0
b) 4567+(1234-4567)-4
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