计算:1-2+3-4+5-6+7-8+…+99-100=______.
题型:填空题难度:一般来源:不详
计算:1-2+3-4+5-6+7-8+…+99-100=______. |
答案
原式=(1-2)+(3-4)+…+(99-100)=-1×=-50. 故答案是-50. |
举一反三
计算: (1)-24-(10-15) (2)(-7)+(+6)-(+9)-(-4) (3)1-(-)+(-)- (4)(-4)-(-5)+(-4)-3. |
计算: (1)(-2.8)-(+1.2); (2)(-6)+(+5); (3)-(-2)-|-3|; (4)(-)-(-0.25); (5)(-0.6)+1.7+(+0.6 )+(-1.7 )+(-9 ); (6)|-2|-(-2.5)+1-|1-2|; (7)3-(-2)+(-)--(+). |
计算: (1)(-121.4)+(-78.5)-(-8)-(-121.4) (2)3-(-2)+(-)--(+). |
计算: (1)(-1.2)+[1-(-0.3)]; (2)(-0.5)-(-3)+2.75-(+7). |
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