计算:1+3-2+2+4-3+3+5-4+4+6-5+…+36+38-37=_.
问题描述:
计算:1+3-2+2+4-3+3+5-4+4+6-5+…+36+38-37=______.
答
1+3-2+2+4-3+3+5-4+4+6-5+…+36+38-37,
=1+2+3+4+5+6+…+37+38-37-2,
=1+2+3+4+5+6+…+36+37+38-39,
=(1+38)×38÷2-39,
=741-39,
=702.
故答案为:702.