问题
填空题
计算:1-2+3-4+5-6+7-8+9-10+11-12+13-14+15=______.
答案
1-2+3-4+5-6+7-8+9-10+11-12+13-14+15,
=(15-14)+(13-12)+(11-10)+(9-8)+(7-6)+(5-4)+(3-1)+1,
=1+1+…+1,
=8;
故答案为:8.
计算:1-2+3-4+5-6+7-8+9-10+11-12+13-14+15=______.
1-2+3-4+5-6+7-8+9-10+11-12+13-14+15,
=(15-14)+(13-12)+(11-10)+(9-8)+(7-6)+(5-4)+(3-1)+1,
=1+1+…+1,
=8;
故答案为:8.