1/1×3 +1/3×5 +1/5×7+1/9×11.1/1999×2001=?

问题描述:

1/1×3 +1/3×5 +1/5×7+1/9×11.1/1999×2001=?

3 23:((7 1) × 9) ÷ 3 24:(7 1) × (9 ÷ 3) (3 5/5)*6=24 (3-1)*(5 7)=24 9/3*(1 7)=24 [(5÷5