99-97+95-93+91-89+87-85...5+3-1(简便计算)
问题描述:
99-97+95-93+91-89+87-85...5+3-1(简便计算)
答
99-97+95-93+91-89+……+7-5+3-1
=(99-97)+(95-93)+(91-89)+……+(7-5)+(3-1)
=2+2+2+……+2+2
=2×25
=50