2-1+3-2+4-3+5-4+.+100-99谢谢了,大神帮忙啊

4*[3/5-(3/4-2/5)]/1/10 （4/5+1/4）÷2/3+3/10 4/5+1/2-3/10-4/5 1/1*2*3+1/2*3*4+1/3*4*5+.+1/8*9*10 (1)12^13(3^10*4^11) (2) (5^4*3^3-5^3*3^2+5^2*3)/15 1*2*3+2*3*4+3*4*5+5*6*7+.10*11*12 1*2*3+2*3*4+3*4*5+5*6*7+.10*11*12 2/3×3/4×10×1/2 1+2+3+4*10 (3/4 ＋ 1/5) * 10/3 ÷ 9/2 /1/3-1/2/+/1/4-1/3/+/1/5-1/4/+.+/1/10-1/9/ |1/3-1/2|+|1/4-1/3|+|1/5-1/4|+...+|1/10-1/9| 英语翻译daily feeding guidelinesweigth lbs weaning-11weeks 3-4 months 5-7 months 8-12 months 3-5 1 - 1 1/3 3/4 -1 1/4 2/3 - 3/4 1/2-2/3 5-10 1 1/3 - 2 1/4 1 1/4 - 2 3/4 - 1 1/3 2/3 - 1 1/4 10-20 2 1/4- 3 2/3 2 - 3 1/4 1 1/3 - 2 1/4 1 - 1 3/4 20-3 “1/2+1/3+2/3+1/4+2/4+3/4+1/5+2/5+3/5+4/5+……+1/10+2/10+3/10+……+8/10+9/10”怎么简便计算啊,帮帮 5+4+3+2+1+8+10+7+18+2 -1/2,2/5,-3/10,4/17的规律性 1+2x/4-1-3x/10>-1/5 (1+2x/4)-(1-3x/10)>-1/5