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(1) 先在长方形里涂色表示$\frac{2}{3}$,然后再计算。
$\frac{2}{3} ÷ \frac{1}{3} = \frac{2}{3} × \frac{( )}{( )} = ( )$
$\frac{2}{3} ÷ \frac{2}{9} = \frac{2}{3} × \frac{( )}{( )} = ( )$
$\frac{2}{3} ÷ \frac{1}{3} = \frac{2}{3} × \frac{( )}{( )} = ( )$
$\frac{2}{3} ÷ \frac{2}{9} = \frac{2}{3} × \frac{( )}{( )} = ( )$
答案
$\frac{2}{3} ÷ \frac{1}{3} = \frac{2}{3} × \frac{3}{1} = 2$
$\frac{2}{3} ÷ \frac{2}{9} = \frac{2}{3} × \frac{9}{2} = 3$
(2) 一个长方形纸片,面积是$\frac{8}{7}$平方米,宽是$\frac{4}{5}$米,长是(
$\frac {10}{7}$
)米。答案
$\frac {10}{7}$
(3) 在“○”里填上“＞”、“＜”或“=”。
$\frac{3}{8} ÷ \frac{5}{6}$ ◯
$\frac{3}{8} × \frac{5}{6}$ ◯
$\frac{4}{5} ÷ \frac{2}{3}$ ◯
$\frac{4}{5} ÷ \frac{3}{2}$ ◯
$\frac{3}{8} ÷ \frac{5}{6}$ ◯
＞
$\frac{3}{8}$$\frac{3}{8} × \frac{5}{6}$ ◯
＜
$\frac{3}{8}$$\frac{4}{5} ÷ \frac{2}{3}$ ◯
＞
$\frac{4}{5}$$\frac{4}{5} ÷ \frac{3}{2}$ ◯
＜
$\frac{4}{5}$答案
＞
＜
＞
＜
2. 火眼金睛辨对错。
(1) $\frac{5}{8} ÷ \frac{1}{8} = \frac{8}{5} × \frac{1}{8} = \frac{1}{5}$ (
(2) $\frac{4}{3} × \frac{5}{2} ÷ \frac{5}{2} × \frac{4}{3} = 1$ (
(3) 甲数除以乙数,等于甲数乘乙数的倒数。(乙数不为 0。) (
(4) 一个真分数除以一个假分数,商一定小于这个真分数。(
(1) $\frac{5}{8} ÷ \frac{1}{8} = \frac{8}{5} × \frac{1}{8} = \frac{1}{5}$ (
×
)(2) $\frac{4}{3} × \frac{5}{2} ÷ \frac{5}{2} × \frac{4}{3} = 1$ (
×
)(3) 甲数除以乙数,等于甲数乘乙数的倒数。(乙数不为 0。) (
×
)(4) 一个真分数除以一个假分数,商一定小于这个真分数。(
×
)答案
×
×
×
×
×
×
×
(1) 下列各算式中,结果最大的是(
A.$\frac{4}{5} × \frac{2}{3}$
B.$\frac{4}{5} - \frac{2}{3}$
C.$\frac{4}{5} ÷ \frac{2}{3}$
D.$\frac{4}{5} + \frac{2}{3}$
D
)。A.$\frac{4}{5} × \frac{2}{3}$
B.$\frac{4}{5} - \frac{2}{3}$
C.$\frac{4}{5} ÷ \frac{2}{3}$
D.$\frac{4}{5} + \frac{2}{3}$
答案
D
(2) 如果$\frac{6}{7} ÷ b ＜ \frac{6}{7}$,那么(
A.$b ＞ 1$
B.$b ＜ 1$
C.$b = 1$
D.无法判断
A
)。A.$b ＞ 1$
B.$b ＜ 1$
C.$b = 1$
D.无法判断
答案
A
(3) $x,y,z$是 3 个非 0 的自然数,且$x ÷ \frac{6}{5} = y ÷ \frac{8}{7} = z ÷ \frac{10}{9}$,那么$x,y,z$按照从大到小的顺序排列应是(
A.$x ＞ y ＞ z$
B.$z ＞ y ＞ x$
C.$y ＞ x ＞ z$
D.$y ＞ z ＞ x$
A
)。A.$x ＞ y ＞ z$
B.$z ＞ y ＞ x$
C.$y ＞ x ＞ z$
D.$y ＞ z ＞ x$
答案
A
4. 直接写得数。
$\frac{2}{7} ÷ \frac{5}{7} = $
$\frac{2}{9} ÷ \frac{1}{4} = $
$\frac{3}{100} ÷ \frac{9}{25} = $
$\frac{1}{6} ÷ \frac{1}{3} = $
$\frac{4}{5} ÷ \frac{5}{4} = $
$\frac{22}{9} ÷ \frac{1}{6} = $
$\frac{1}{8} ÷ \frac{5}{2} = $
$\frac{5}{12} ÷ \frac{1}{3} = $
$\frac{2}{7} ÷ \frac{5}{7} = $
$\frac{2}{5}$
$\frac{2}{9} ÷ \frac{1}{4} = $
$\frac{8}{9}$
$\frac{3}{100} ÷ \frac{9}{25} = $
$\frac{1}{12}$
$\frac{1}{6} ÷ \frac{1}{3} = $
$\frac{1}{2}$
$\frac{4}{5} ÷ \frac{5}{4} = $
$\frac{16}{25}$
$\frac{22}{9} ÷ \frac{1}{6} = $
$\frac{44}{3}$
$\frac{1}{8} ÷ \frac{5}{2} = $
$\frac{1}{20}$
$\frac{5}{12} ÷ \frac{1}{3} = $
$\frac{5}{4}$
答案
$\frac{2}{5}$
$\frac{8}{9}$
$\frac{1}{12}$
$\frac{1}{2}$
$\frac{16}{25}$
$\frac{44}{3}$
$\frac{1}{20}$
$\frac{5}{4}$
$\frac{8}{9}$
$\frac{1}{12}$
$\frac{1}{2}$
$\frac{16}{25}$
$\frac{44}{3}$
$\frac{1}{20}$
$\frac{5}{4}$
5. 解方程。
$\frac{5}{8}x = \frac{5}{4}$
$\frac{9}{10}x = \frac{6}{7}$
$\frac{3}{7}x = \frac{6}{49}$
$\frac{2}{25}x = \frac{4}{5}$
$\frac{5}{8}x = \frac{5}{4}$
$\frac{9}{10}x = \frac{6}{7}$
$\frac{3}{7}x = \frac{6}{49}$
$\frac{2}{25}x = \frac{4}{5}$
答案
$\frac{5}{8}x = \frac{5}{4}$
解：$x = \frac{5}{4} ÷ \frac{5}{8}$
$x = \frac{5}{4} × \frac{8}{5}$
$x = 2$
$\frac{9}{10}x = \frac{6}{7}$
解：$x = \frac{6}{7} ÷ \frac{9}{10}$
$x = \frac{6}{7} × \frac{10}{9}$
$x = \frac{20}{21}$
$\frac{3}{7}x = \frac{6}{49}$
解：$x = \frac{6}{49} ÷ \frac{3}{7}$
$x = \frac{6}{49} × \frac{7}{3}$
$x = \frac{2}{7}$
$\frac{2}{25}x = \frac{4}{5}$
解：$x = \frac{4}{5} ÷ \frac{2}{25}$
$x = \frac{4}{5} × \frac{25}{2}$
$x = 10$
解：$x = \frac{5}{4} ÷ \frac{5}{8}$
$x = \frac{5}{4} × \frac{8}{5}$
$x = 2$
$\frac{9}{10}x = \frac{6}{7}$
解：$x = \frac{6}{7} ÷ \frac{9}{10}$
$x = \frac{6}{7} × \frac{10}{9}$
$x = \frac{20}{21}$
$\frac{3}{7}x = \frac{6}{49}$
解：$x = \frac{6}{49} ÷ \frac{3}{7}$
$x = \frac{6}{49} × \frac{7}{3}$
$x = \frac{2}{7}$
$\frac{2}{25}x = \frac{4}{5}$
解：$x = \frac{4}{5} ÷ \frac{2}{25}$
$x = \frac{4}{5} × \frac{25}{2}$
$x = 10$
