?????????????????????￥???? ???????????????￥??????

???????????????￥????????

??￥????????

???1~100￥

1-10????1160

11-20????2650

21-30????5770

31-40????13500

41-50????20200

51-60????24200

61-70????28200

71-80????32750

81-90 ????37750

91-100 ????42750

1~100￥?????208930

????￥?佫????

??1??4510????????????????10????

?????????????

Sn=(a1+an)n/2

Sn=na1+n(n-1)d/2; (d?????)

Sn=An2+Bn; A=d/2,B=a1-(d/2)

??1????10???? 45550

????20???? 92100

????30???? 139650

????40???? 188200

????50???? 237750

????60???? 288300

????70???? 339850

????80???? 392400

????90???? 445950

????100???? 500500

??????????????????????￥????????????????а?????????!