1. 直接写出得数。
$\frac{1}{6}+\frac{1}{6}=$ $\frac{7}{9}-\frac{2}{9}=$ $\frac{(\quad)}{(\quad)}-\frac{1}{3}=\frac{1}{3}$ $\frac{1}{10}+\frac{7}{10}+\frac{1}{10}=$
$\frac{1}{7}+\frac{4}{7}=$ $\frac{6}{8}-\frac{4}{8}=$ $\frac{6}{7}-\frac{(\quad)}{(\quad)}=\frac{4}{7}$ $\frac{8}{11}-\frac{5}{11}+\frac{7}{11}=$
$\frac{3}{9}+\frac{5}{9}=$ $\frac{6}{7}-\frac{5}{7}=$ $\frac{(\quad)}{(\quad)}+\frac{4}{10}=1$ $\frac{2}{8}+\frac{2}{8}+\frac{2}{8}=$
$\frac{8}{12}-\frac{5}{12}=$ $\frac{2}{4}+\frac{1}{4}=$ $\frac{(\quad)}{(\quad)}-\frac{7}{9}=\frac{2}{9}$ $\frac{3}{4}-\frac{2}{4}+\frac{1}{4}=$
$\frac{3}{3}-\frac{2}{3}=$ $\frac{2}{5}+\frac{2}{5}=$ $\frac{9}{12}-\frac{(\quad)}{(\quad)}=0$ $\frac{4}{5}-\frac{2}{5}+\frac{1}{5}=$

1. $\dfrac{2}{6}$ $\dfrac{5}{9}$ $\dfrac{2}{3}$ $\dfrac{9}{10}$
$\dfrac{5}{7}$ $\dfrac{2}{8}$ $\dfrac{2}{7}$ $\dfrac{10}{11}$
$\dfrac{8}{9}$ $\dfrac{1}{7}$ $\dfrac{6}{10}$ $\dfrac{6}{8}$
$\dfrac{3}{12}$ $\dfrac{3}{4}$ $\dfrac{9}{9}$ $\dfrac{2}{4}$
$\dfrac{1}{3}$ $\dfrac{4}{5}$ $\dfrac{9}{12}$ $\dfrac{3}{5}$

2. 计算下面各题。
$217÷7×23$ $18×3×42$ $550÷5-39$
$17×32÷8$ $248-636÷3$ $121+448×4$

2. 713 2268 71
68 36 1913

将一张长方形纸对折、再对折……观察并填写下表。

思维提升
2 4 8 16 32
$\dfrac{1}{2}$ $\dfrac{1}{4}$ $\dfrac{1}{8}$ $\dfrac{1}{16}$ $\dfrac{1}{32}$