2+4+6+......+16+18+20
=(2+20)+(4+18)+(6+16)+(8+14)+(10+12)
=22*5=110
或者直接套用公式:
2+4+6+......+16+18+20
=(2+20)*10/2
=22*5=110
2+4+6+...16+18+20
=(2+18)+(4+16)+(6+14)+(8+12)+20+10
=20×5+10
=100+10
=110
你好!问题已回答,能点击右下角的采纳答案吗?谢谢了
2+4+6+......+16+18+20
=(2+20)+(4+18)+(6+16)+(5+15)+(4+14)+(3+13)+(2+12)+(1+10)
=8*22
=176
2+4+6+8+10+12+14+16+18+20
=(2+18)+(4+16)+(6+14)+(8+12)+(10+20
)=
20+20+20=+20+30=110