$\frac{1}{10}$ + $\frac{2}{5}$ =____

$\frac{5}{6}$ ﹣ $\frac{2}{3}$ =____

$\frac{1}{3}$ + $\frac{1}{5}$ =____

$\frac{3}{8}$ ﹣ $\frac{1}{4}$ =____

$\frac{3}{8}$ ﹣ $\frac{1}{3}$ =____

$\frac{9}{8}$ + $\frac{2}{15}$ + $\frac{7}{8}$ =____

3 $\frac{5}{6}$ ﹣ $\frac{3}{4}$ ﹣ $\frac{1}{4}$ =____

$\frac{11}{12}$ ﹣（ $\frac{7}{12}$ + $\frac{1}{8}$ ）=____

11﹣ $\frac{1}{10}$ ﹣ $\frac{3}{10}$ =____

$\frac{7}{12}$ ﹣（ $\frac{3}{4}$ ﹣ $\frac{1}{2}$ ）=____  

$\frac{3}{4}$ ﹣（ $\frac{3}{4}$ ﹣ $\frac{3}{8}$ ）=____

下列属于生物的是（  ）

水的密度是1.0×10³千克/米³，它表示____ 

—Which is the biggest number of the four?
—                           ．