2.4+3/5= 1/7+1/11= 3/8+0.125= 10-2/5=

2.4+3/5= 1/7+1/11= 3/8+0.125= 10-2/5= (-0.125)+(+5)+(-7)+(+1\8)+(+2)=? 解方程.25/7+x=2/1 x-10/3=8/5 11/5-x=5/1 10/21+(3/20+11/21)= 3/18+5/8-2/18= 7/15-1/5= 2/3-1/3+1/6= 1- 5/7+1/8=?2/3+5/9=?3/8+7/12=?4/5-3/10=?8/9-5/7=?11/14-21/11=? 1+2-3-4+5+5-7-8+9+10-11-12+.+2009=? 排列组合公式C(11,5)=11*10*9*8*7/5*4*3*2*1=462 a[2][4]={1,2,3,4,5,6,7,8};b[4][3]={1,2,3,4,5,6,7,8,9,10,11,1 1*1*2*3*4*5*6*7*8*9*10*11*12.*20=? 3/5X-1/4X=7 8/11:10=4/5：X 3X-16×5=13 X：2/3=0.25:0.2 3/10÷20= 9÷3/4= 5/8×1/4= 6/11×5/12= 5/9-1/6= 2/3÷4/7= 1/8+3/ 5^2-1^2=24=8×3 7^2-1^2=48=8×6 11^2-3^2=112=8×14