1. $\frac{5}{9}$表示( )个$\frac{1}{9}$,$\frac{3}{9}$表示( )个$\frac{1}{9}$,所以$\frac{5}{9} + \frac{3}{9}$得( )个$\frac{1}{9}$,也就是( )。
答案:
5 3 8 $\frac{8}{9}$
2. $\frac{4}{15} - \frac{2}{15}$表示( )个$\frac{1}{15}$减去( )个$\frac{1}{15}$,得( )个$\frac{1}{15}$,差是( )。
答案:
4 2 2 $\frac{2}{15}$
3. 同分母分数相加减,( )不变,只把( )相加减,计算的结果,能约分的要( )。
答案:
分母 分子 约分
4. $\frac{(\ \ \ \ \ )}{5} = \frac{(\ \ \ \ \ )}{9} = \frac{15}{(\ \ \ \ \ )} = \frac{(\ \ \ \ \ )}{(\ \ \ \ \ )} = 1$(最后两空不唯一)
答案:
5 9 15 $\frac{7}{7}$(不唯一)
二、我是小法官。
1. $\frac{5}{8} + \frac{7}{8} = \frac{12}{16}$ ( )
2. $\frac{15}{17} - \frac{13}{17} = \frac{12}{0} = 0$ ( )
3. $\frac{11}{19} - \frac{7}{19} - \frac{4}{19} = \frac{4}{19} - \frac{4}{19} = 0$ ( )
4. $1 - \frac{3}{4} + \frac{1}{4} = 0$ ( )
1. $\frac{5}{8} + \frac{7}{8} = \frac{12}{16}$ ( )
2. $\frac{15}{17} - \frac{13}{17} = \frac{12}{0} = 0$ ( )
3. $\frac{11}{19} - \frac{7}{19} - \frac{4}{19} = \frac{4}{19} - \frac{4}{19} = 0$ ( )
4. $1 - \frac{3}{4} + \frac{1}{4} = 0$ ( )
答案:
×
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三、我能在括号里填合适的数。
$\frac{11}{15} + \frac{8}{15} =$ ( ) $- \frac{2}{15}$
$\frac{4}{7} +$ ( ) $= \frac{2}{7} + \frac{3}{7}$
$\frac{8}{9} - \frac{2}{9} =$ ( ) $+ \frac{5}{9}$
$\frac{7}{14} = 1 -$ ( ) $-$ ( )(不唯一)
$\frac{11}{15} + \frac{8}{15} =$ ( ) $- \frac{2}{15}$
$\frac{4}{7} +$ ( ) $= \frac{2}{7} + \frac{3}{7}$
$\frac{8}{9} - \frac{2}{9} =$ ( ) $+ \frac{5}{9}$
$\frac{7}{14} = 1 -$ ( ) $-$ ( )(不唯一)
答案:
$\frac{21}{15}$ $\frac{1}{7}$ $\frac{1}{9}$ $\frac{2}{14}$ $\frac{5}{14}$(不唯一)
1. 直接写得数。
$\frac{2}{6} + \frac{1}{6} =$ $\frac{3}{7} + \frac{2}{7} =$
$\frac{3}{18} + \frac{5}{18} =$ $\frac{9}{16} - \frac{7}{16} =$
$\frac{7}{15} - \frac{4}{15} =$ $\frac{3}{4} + \frac{1}{4} =$
$\frac{17}{24} - \frac{7}{24} =$ $\frac{9}{12} + \frac{1}{12} =$
$\frac{2}{6} + \frac{1}{6} =$ $\frac{3}{7} + \frac{2}{7} =$
$\frac{3}{18} + \frac{5}{18} =$ $\frac{9}{16} - \frac{7}{16} =$
$\frac{7}{15} - \frac{4}{15} =$ $\frac{3}{4} + \frac{1}{4} =$
$\frac{17}{24} - \frac{7}{24} =$ $\frac{9}{12} + \frac{1}{12} =$
答案:
$\frac{1}{2}$ $\frac{5}{7}$ $\frac{4}{9}$ $\frac{1}{8}$ $\frac{1}{5}$ 1 $\frac{5}{12}$ $\frac{5}{6}$
2. 算一算。
$\frac{6}{17} + \frac{3}{17} + \frac{9}{17}$
$\frac{4}{9} + \frac{2}{9} + \frac{1}{9}$
$1 - \frac{5}{18} - \frac{7}{18}$
$\frac{27}{28} - \frac{5}{28} - \frac{11}{28}$
$\frac{6}{17} + \frac{3}{17} + \frac{9}{17}$
$\frac{4}{9} + \frac{2}{9} + \frac{1}{9}$
$1 - \frac{5}{18} - \frac{7}{18}$
$\frac{27}{28} - \frac{5}{28} - \frac{11}{28}$
答案:
$\frac{18}{17}$ $\frac{7}{9}$ $\frac{1}{3}$ $\frac{11}{28}$
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