计算:1-2+3-4+…+2007-2008+2009=______.
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计算:1-2+3-4+…+2007-2008+2009=______.
![计算:1-2+3-4+…+2007-2008+2009=______.](/uploads/image/z/15896448-0-8.jpg?t=%E8%AE%A1%E7%AE%97%EF%BC%9A1-2%2B3-4%2B%E2%80%A6%2B2007-2008%2B2009%3D______%EF%BC%8E)
1-2+3-4+…+2007-2008+2009
=1+[(3-2)+(5-4)+…+(2009-2008)]
=1+1004
=1005
故答案为:1005.
=1+[(3-2)+(5-4)+…+(2009-2008)]
=1+1004
=1005
故答案为:1005.
计算:1-2+3-4+5-6+…+2009-2010=______.
计算:1×2+2×4+3×6+…+1005×2010=______.
计算:200-199+198-197+…+4-3+2-1=______.
计算:120-119+118-117+116-115+…+4-3+2-1=______.
计算:1-2+3-4+…+97-98+99=______.
计算:1-2+3-4+5-6+…+87-88=______.
计算:1-2+3-4+5-…-98+99=______.
计算:1-2-3+4+5-6-7+8+…+2005-2006-2007+2008等于______.
计算:1-2-3+4+5-6-7+8+9-…+2004+2005-2006-2007+4017=______.
计算有规律的2010个数的算式:1-2+3-4+5-6+…+2009-2010=______.
计算:(-4x-3y)2=______.
算式2011-2009+2007-2005+…-…+3-1的计算结果是______.