1+2+3+4+5+6+7+8+9+10 (55)+11+12+13+14+15+16+17+18+19+20(155)+21+22+23+24+25+26+27+28+29+30( 255) +31+32+33+34+35+36+37+38+39+40(355)
55+155+255+355=820
终于算出来了
1+2+3+4+5+6+7+8+9+10 (55)+11+12+13+14+15+16+17+18+19+20(155)+21+22+23+24+25+26+27+28+29+30( 255) +31+32+33+34+35+36+37+38+39+40(355)
55+155+255+355=820
终于算出来了