80!=1*2*3*······*79*80,这个数的末尾共有()个0

急·····················1+2+3+...+999=? 80!=1*2*3*······*79*80,这个数的末尾共有()个0 1+2++3+··········+10000= 1 2 3 4 ·····7 ·······10 ········?1 3 5 7 ·····?······?··········290 1 4 9 ·····?······?··········? 变态数学题·······方程一道············x+2y+3z=1x=y+12x+3y+5z=2方程组············要过程············我解了之后总觉得无解····· 在等腰三角形ABC中,AB=AC.求证1、∠BAD=∠CAE 2、如果AD=AE,那么BD=CE吗?急啊························································· 1/3+2/3=1,但0.333···+0.666···=0.999···,为神马?额······谁能解释一下······ 2[4/3y—（2/3y—1/2）]=3/4y急·································!1 8+11+14+17+20+·······+305 数学计算题.呜呜呜1+2+3+4+···················+98+99+100+99+98+···············+3+2+1 300*1+300*2+300*3+···················300*30=?这种题目怎么换算的急, 秦始皇和汉武帝各自的功劳是?（用1·······2·······3··········来说） 1乘2+2乘3+·········100乘101=多少 俗语和名句的填空1······,自知之明.2······,行必果.3工欲善其事,······.4临渊羡鱼,······.5非学无以广才,······.6······,福兮祸之所伏.7项庄舞剑,······.8······,人以群 1+2+3+4+······+78+79+801/2+1/6+1/12+1/20+······+1/72+1/90100-99+98-97+96-······+4-3+2-11000-1-2-3-4-······-78-79-801/15+2/15+······+13/15+14/15注：例 1/15 就是 十五分之一 纸鹤数量的意义比如说 1只纸鹤,代表······· 2只纸鹤,代表······· ······················· ···························· ·················· 越多越好, （1994+1992+······+4+2）—（1+3+5+······+1991+1993）=（ ） （1+3+5++7+9······+2011）-（2+4+6+8······+2012）= 已知三个角1,2,3满足：1与2互补,2与3互余,试求1-3的大小!·································