88+95+92+89+86+91+90+88+92+90+86+92+87+89+91+93+88+94+91+87 =(88+92)+(89+91)+(90+90)+(88+92)+(86+94)+(92+88)+(87+93)+(89+91) +(95+86+91+87)
=180×8+359
=1799
或
取基数=90
则原来的20个加数分别=
-2,+5,+2,-1,+4,+1,0,-2,+2,0,-4,+2,-3,-1,+1,+3,-2,+4,+1,-3。
求它们的和=-1,
∴总和=90×20-1=1799
88+95+92+89+86+91+90+88+92+90+86+92+87+89+91+93+88+94+91+87
=90x20+(-2+5+2-1-4+1+0-2+2+0-4+2-3-1+1+3-2+4+1-3)=1799