来自李洪心的问题
(口算)4+6+8+10+12+14+16+18+20+22+24+26+28+30+32+34+36.
(口算)4+6+8+10+12+14+16+18+20+22+24+26+28+30+32+34+36.
1回答
2020-08-02 10:45
(口算)4+6+8+10+12+14+16+18+20+22+24+26+28+30+32+34+36.
(口算)4+6+8+10+12+14+16+18+20+22+24+26+28+30+32+34+36.
4+6+8+10+12+14+16+18+20+22+24+26+28+30+32+34+36
=(4+36)×17÷2
=40×17÷2
=340