1×2/1+2×3/1+3×4/1+…+98×99/1+99×100/1 用简便方法计算
问题描述:
1×2/1+2×3/1+3×4/1+…+98×99/1+99×100/1 用简便方法计算
答
1×2/1+2×3/1+3×4/1+…+98×99/1+99×100/1
=1-2/1+2/1-3/1+3/1-4/1+……+99/1-100/1
=1-100/1
=100/99