作业帮计算1989+1988+1987-1986-1985-1984+1983+1982+1981-1980-1979-1978+·····+9请尽快发出答案
来源：学生作业帮助网 编辑：作业帮 时间：2024/09/29 13:13:27
x){nu
--,0f DČA0 sKa}h; j[X醽O~?ik<[aTOe{ FbLΆ~ޢl-APOODC
9=<;m *HKd1NBr ɖ
计算1989+1988+1987-1986-1985-1984+1983+1982+1981-1980-1979-1978+·····+9请尽快发出答案
计算1989+1988+1987-1986-1985-1984+1983+1982+1981-1980-1979-1978+·····+9
请尽快发出答案
计算1989+1988+1987-1986-1985-1984+1983+1982+1981-1980-1979-1978+·····+9请尽快发出答案
1989+1988+1987-1986-1985-1984+1983+1982+1981-1980-1979-1978+·····+9
=9+9+9+...+9+9
=9*330+9
=9*331
=2979.
1989+1988+1987-1986-1985-1984+1983+1982+1981-1980-1979-1978+·····+9
=9*(1989-9)/6+9
=9*330+9
=9*331
=2979