Câu 1:
= -32 - y - 20 + 20
= - y - 32
Câu 2:
= 468 + 333 -(2017 + 345)
= 468 + 333 - 2017 + 345
= -1561
Câu 3:
a) = -69 + 53 + 46 - 94 - 14 + 78
= 0
b) = 13
Câu 4:
A=1-3+5-7+...+2001-2003+2005
A=(1-3)(5-7)+...+(2001-2003)+2005
A=2×501+2005
A=1003
C=1+2-3-4+5+6-7-8+9+...+2002-2003-2004+2005+2006
C=1+(2-3-4+5)+(6-7-8+9)+...+(2002-2003-2004+2005)+2006
C=1+0+0+...+0+2006
C=1+2006
C=2007