1. 看图,填一填。
(1) $+$
=
+
=
$\frac{1}{2}+\frac{1}{3}=(\quad)+(\quad)=(\quad)$
(2) $-$ $=$ $-$ $(\quad)-(\quad)=(\quad)-(\quad)=(\quad)$
(1) $+$
(2) $-$ $=$ $-$ $(\quad)-(\quad)=(\quad)-(\quad)=(\quad)$
答案
1.(1)$\frac{3}{6}+\frac{2}{6}=\frac{5}{6}$
(2)$\frac{1}{2}-\frac{1}{4}=\frac{2}{4}-\frac{1}{4}=\frac{1}{4}$
(2)$\frac{1}{2}-\frac{1}{4}=\frac{2}{4}-\frac{1}{4}=\frac{1}{4}$
(1)一个数比$\frac{1}{2}$大$\frac{1}{4}$,这个数是(
A.$\frac{2}{6}$
B.$\frac{3}{4}$
C.$\frac{2}{4}$
B
)。A.$\frac{2}{6}$
B.$\frac{3}{4}$
C.$\frac{2}{4}$
答案
(1)B
(2)一块木料有$\frac{7}{8}$米,用去$\frac{1}{4}$米,还剩(
A.$1\frac{1}{8}$
B.$\frac{3}{2}$
C.$\frac{5}{8}$
C
)米。A.$1\frac{1}{8}$
B.$\frac{3}{2}$
C.$\frac{5}{8}$
答案
(2)C
3. 算一算。
$\frac{3}{8} - \frac{1}{4} =$
$\frac{5}{9} + \frac{1}{3} =$
$\frac{8}{9} + \frac{1}{18} =$
$\frac{4}{5} - \frac{8}{20} =$
$\frac{5}{6} + \frac{1}{3} =$
$1 - \frac{3}{10} =$
$\frac{1}{12} + \frac{1}{4} =$
$\frac{19}{24} - \frac{1}{6} =$
$\frac{3}{8} - \frac{1}{4} =$
$\frac{5}{9} + \frac{1}{3} =$
$\frac{8}{9} + \frac{1}{18} =$
$\frac{4}{5} - \frac{8}{20} =$
$\frac{5}{6} + \frac{1}{3} =$
$1 - \frac{3}{10} =$
$\frac{1}{12} + \frac{1}{4} =$
$\frac{19}{24} - \frac{1}{6} =$
答案
$\frac{1}{8}\quad \frac{8}{9}\quad \frac{17}{18}\quad \frac{2}{5}\quad \frac{7}{6}\quad \frac{7}{10}\quad \frac{1}{3}\quad \frac{5}{8}$
4. 解方程。
$\frac{5}{24} - x = \frac{1}{8}$
$x - \frac{1}{10} = \frac{1}{3}$
$x - \frac{5}{8} = \frac{5}{12}$
$\frac{5}{24} - x = \frac{1}{8}$
$x - \frac{1}{10} = \frac{1}{3}$
$x - \frac{5}{8} = \frac{5}{12}$
答案
$x=\frac{1}{12}\quad x=\frac{13}{30}\quad x=\frac{25}{24}$
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