199×(1-2/1)×(1-3/1)×(1-4/1)×...÷(1-199/1)=?
计算:200-199+198-197+…+4-3+2-1=______.
100×199-199×198+198×197-197×196+…+2×1=______.
199-198+197-196+195-194+…+5-4+3-2+1.
(-1/2)^199+(-1/2)^200=?
1+2+3+...+198+199+200=?
计算:(1+3+5+7+…+199+201)-(2+4+6+8+…+198+200).
简算.1/1X2+1/2X3+1/3X4+1/4X5+.+1/199X200,
简便计算:1/1×2+1/2×3+1/3×4+...+1/199×200
(1+3+5+7+...+199)/(2+4+6+...+200)=
1+2+3+4+.+197+198+199+200=?
1-1/2+1/3-1/4+1/5+1/6+1/7-----------+1/199-1/200
1×2+3×4+5×6+…+199×200的和是______【填“奇数”还是“偶数”】.