梯形的高=梯形的面积÷(上底+下底)×2. (判断对错)
:12=5÷4== %= (填小数).
3÷4=9: == 填分数= (填小写)
9: =0.75==21÷ = :4.
5÷8= : = = %.
:4=0.75== %