灵活运用所学知识进行巧算. 4000-5-10-15-…-95-100.
问题描述:
灵活运用所学知识进行巧算.
4000-5-10-15-…-95-100.
答
4000-5-10-15-…-95-100=4000-(5+10+15+…+100),
项数=(100-5)÷5+1=20,
4000-5-10-15-…-95-100,
=4000-(5+10+15+…+100),
=4000-[(5+100)×20÷2],
=4000-1050,
=2950.