题目内容
化简下列各比,并求比值
105:35
:
.
85:0.5
40千克:0.8吨.
105:35
4 |
5 |
1 |
4 |
85:0.5
40千克:0.8吨.
分析:(1)有单位名称的先把比的两项的单位统一,再根据比的基本性质作答,即比的前项和后项同时乘或除以一个数(0除外)比值不变;
(2)用比的前项除以后项,如果有单位名称,要先把单位统一,再用比的前项除以后项即可.
(2)用比的前项除以后项,如果有单位名称,要先把单位统一,再用比的前项除以后项即可.
解答:解:(1)105:35,
=(105÷35):(35÷35),
=3:1;
105:35,
=105÷35,
=3,
(2)
:
,
=(
×20):(
×20),
=16:5,
:
,
=
÷
,
=
,
(3)85:0.5,
=(85×2):(0.5×2),
=170:1;
85:0.5,
=85÷0.5,
=170,
(4)40千克:0.8吨,
=40千克:800千克,
=40:800,
=(40÷40):(800÷40),
=1:20;
40千克:0.8吨,
=40千克:800千克,
=40÷800,
=
.
=(105÷35):(35÷35),
=3:1;
105:35,
=105÷35,
=3,
(2)
4 |
5 |
1 |
4 |
=(
4 |
5 |
1 |
4 |
=16:5,
4 |
5 |
1 |
4 |
=
4 |
5 |
1 |
4 |
=
16 |
5 |
(3)85:0.5,
=(85×2):(0.5×2),
=170:1;
85:0.5,
=85÷0.5,
=170,
(4)40千克:0.8吨,
=40千克:800千克,
=40:800,
=(40÷40):(800÷40),
=1:20;
40千克:0.8吨,
=40千克:800千克,
=40÷800,
=
1 |
20 |
点评:此题考查化简比和求比值的方法,要注意区分:化简比是根据比的基本性质进行化简的,结果仍是一个比;求比值是用比的前项除以后项所得的商,结果是一个数,可以是小数、分数和整数.
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