2 分数乘法
把这两个
正六边形的面积和看成1,
(1)则
可以表示为 (用阴影部分标出);
所以,
的
可以表示为(用
阴影部分标出),占整个图形面积的 (用分数表示)
所以,
×
= .
(2)请你利用上述
的图形,模仿上述的过程编写一个用图形面积说明分数乘法的式子:
×
可以表示为
(用阴影部分标出)
所以, 的 可以表示为
(用阴影部分标出),占整个图形面积的 .(用分数表示)
所以, × = .
直接写出得数(最后4题为估算):
×
= 1﹣
+
= 0.6×
= 5.2÷(1+0.3)=
87×22≈ 724÷31≈ 816+991≈ 7.18×5.89≈
直接写出得数:
1÷5×
=
×
=
÷26=
﹣
= 0.8÷0.02=
1.25×16= 2﹣2÷3= 100×0.1%= 0.625+
= 6.5×11﹣6.5=
直接写出得数.
+0.625= 1÷0.05= 9.7+0.05=
×
=
78×9.9+7.8= 12﹣2
= 10÷10%= 1﹣
﹣
﹣
=
6
﹣
﹣4.25=
+
﹣
+
=





是多少?
×
=
.
公顷的
.
= ;
×
= ; 35×
= ;
×
= ;
×
= ;
×
= ;
×18= ;
×
= .
= ;
= ;
= ;
= ;
= ;
= ;
= ;
= .
×
=
×
= 0.9×
=
=
×
= 80×
×
=
×0=
×
=
×12=
×
=
×
=
×
= 9×
=
×
=
=
×
=
×
=
×
=
×75 (2)
×
(3)
×
×
(5)
×
×
(6)
×
×
.
×
=
×
=
×
=
×
=
+
×
×
×
=
×40=
﹣
=
×
= 2×
= 24×
=
×22= 18×
=
×
=
×
=
×
=
×15=
×2=
×
=
×
=
×
= 1×
=
×
=
×34=
×
=
×
=
×
=
×
=
×4.8 2
×3.5 2.3×1
2
×0.63.
×15=
×2=
×
=
×
=
=
×
=
×34=
×
=
×
=
×
=
×
=
×
=
×15=
×2=
×
=
×
=
×
=
=
×
=
×34=
×
=
×
=
×
=
×
=
×
=
×
=
×
=
×24=
×
=
×30= 28×
=
×
=
×
=
×
=
×9=
×
×0=
+
=
×11= 5﹣
﹣
=
×9×7=
=
×5=
×
= 12×
= 3×
=
= 4.8+0.82= 3
﹣2.7= (
+2)×9= (
﹣
)×2=
=
=
=
=
=
=
= (
﹣
)×30=
×
=
×21=
×
=
=
=
×
=
×
=
×5=
是多少?
千米的
是多少千米?
是多少吨?
的
是多少?
=
=
=
=
=
=
=
=
×
×
=
×5=
×
=
×
= 42×π= 22×π= 32π=
×8=
= 4.5+
= 26×
= 7﹣
=
×0×14= 6×
= 5﹣
=
×6= 45×
=
×3
4
×2
1
×2
×3
×
11×3
×
2
×
.
×1=
×
=
×12=
×
=
=
=
×
=
×50= 6×
=
×
=
,乙数是5,丙数是甲数的倒数,这三个数的积是多少?
﹣
=
×
×0= 1÷25%= 7﹣
= 10×
=
÷2= 4×
×
=
=
×14=
×
×0=
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