1. 根据乘法运算定律填空。
(1)$\frac {4}{5}×\frac {3}{8}×\frac {5}{4}= ($
(2)$(\frac {2}{3}+\frac {3}{4})×12$
$= ($
(3)$\frac {3}{4}×\frac {6}{7}+\frac {3}{4}×\frac {1}{7}= \frac {3}{4}×[($
(4)$\frac {5}{9}×29-\frac {5}{9}×2= \frac {5}{9}×[($
(1)$\frac {4}{5}×\frac {3}{8}×\frac {5}{4}= ($
$\frac{4}{5}$
$)×($$\frac{5}{4}$
$)×\frac {3}{8}$(2)$(\frac {2}{3}+\frac {3}{4})×12$
$= ($
$\frac{2}{3}$
$)×($12
$)+($$\frac{3}{4}$
$)×($12
$)$(3)$\frac {3}{4}×\frac {6}{7}+\frac {3}{4}×\frac {1}{7}= \frac {3}{4}×[($
$\frac{6}{7}$
$)+($$\frac{1}{7}$
$)]$(4)$\frac {5}{9}×29-\frac {5}{9}×2= \frac {5}{9}×[($
29
$)-($2
$)]$
答案:
1.
(1)$\frac{4}{5}$ $\frac{5}{4}$
(2)$\frac{2}{3}$ 12 $\frac{3}{4}$ 12
(3)$\frac{6}{7}$ $\frac{1}{7}$
(4)29 2
(1)$\frac{4}{5}$ $\frac{5}{4}$
(2)$\frac{2}{3}$ 12 $\frac{3}{4}$ 12
(3)$\frac{6}{7}$ $\frac{1}{7}$
(4)29 2
2. 火眼金睛辨对错。(对的画“√”,错的画“×”)
(1)$\frac {6}{7}×\frac {1}{3}+\frac {1}{3}= \frac {6}{7}$ (
(2)$(6+\frac {3}{5})×5= 9$ (
(3)$\frac {5}{6}-\frac {1}{6}×\frac {3}{4}= \frac {1}{2}$ (
(4)$\frac {1}{3}+\frac {1}{5}-\frac {1}{3}+\frac {1}{5}= 0$ (
(1)$\frac {6}{7}×\frac {1}{3}+\frac {1}{3}= \frac {6}{7}$ (
×
)(2)$(6+\frac {3}{5})×5= 9$ (
×
)(3)$\frac {5}{6}-\frac {1}{6}×\frac {3}{4}= \frac {1}{2}$ (
×
)(4)$\frac {1}{3}+\frac {1}{5}-\frac {1}{3}+\frac {1}{5}= 0$ (
×
)
答案:
2.
(1)×
(2)×
(3)×
(4)×
(1)×
(2)×
(3)×
(4)×
3. 计算下面各题。(能简算的要简算)
$\frac {4}{5}×\frac {7}{10}+\frac {4}{5}×\frac {3}{10}$ $\frac {8}{17}÷23+\frac {1}{23}×\frac {9}{17}$
$(\frac {3}{4}-\frac {5}{8})×\frac {8}{9}$ $36×(\frac {4}{9}+\frac {5}{6})$
$\frac {7}{12}×\frac {5}{9}+\frac {7}{12}÷\frac {9}{4}$ $\frac {8}{3}-\frac {4}{5}-\frac {1}{5}$
$\frac {4}{5}×\frac {7}{10}+\frac {4}{5}×\frac {3}{10}$ $\frac {8}{17}÷23+\frac {1}{23}×\frac {9}{17}$
$(\frac {3}{4}-\frac {5}{8})×\frac {8}{9}$ $36×(\frac {4}{9}+\frac {5}{6})$
$\frac {7}{12}×\frac {5}{9}+\frac {7}{12}÷\frac {9}{4}$ $\frac {8}{3}-\frac {4}{5}-\frac {1}{5}$
答案:
3. $\frac{4}{5}$ $\frac{1}{23}$ $\frac{1}{9}$ 46 $\frac{7}{12}$ $\frac{5}{3}$
4.
两种瓜子各买2袋,一共重多少千克?
两种瓜子各买2袋,一共重多少千克?
答案:
4. $2×\frac{1}{4}+2×\frac{1}{5}=\frac{9}{10}$(千克)
5. 少先队员采集植物标本120件,其中中年级采集了$\frac {1}{4}$,高年级采集了$\frac {3}{5}$,其余的是低年级采集的。
(1)中、高年级一共采集了多少件?
(2)高年级比中年级多采集了多少件?
(1)中、高年级一共采集了多少件?
(2)高年级比中年级多采集了多少件?
答案:
5.
(1)$120×\frac{1}{4}+120×\frac{3}{5}=102$(件)
(2)$120×\frac{3}{5}-120×\frac{1}{4}=42$(件)
(1)$120×\frac{1}{4}+120×\frac{3}{5}=102$(件)
(2)$120×\frac{3}{5}-120×\frac{1}{4}=42$(件)
6. 素养题 一本《古诗文鉴赏》共120页,小辰第一天看了全书的$\frac {1}{6}$,第二天看了全书的$\frac {1}{4}$。他第三天应从第几页开始看?
答案:
6. $120×\frac{1}{6}+120×\frac{1}{4}=50$(页) 50+1=51(页)
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