考點(diǎn):求比值和化簡(jiǎn)比
專題:比和比例
分析:(1)根據(jù)比的基本性質(zhì)作答,即比的前項(xiàng)和后項(xiàng)同時(shí)乘一個(gè)數(shù)或除以一個(gè)數(shù)(0除外)比值不變;
(2)用比的前項(xiàng)除以后項(xiàng)即可.
解答:
解:(1)1.3:39
=(1.3×
):(39×
)
=1:30;
1.3:39
=1.3÷39
=
;
(2)
:
=(
×12):(
×12)
=3:2;
:
=3÷2
=1.5;
(3)
:0.6
=(
×10):(0.6×10)
=5:6;
:0.6
=5÷6;
=
(4)2米:4厘米
=(2×100厘米):4厘米
=200:4
=(200÷4):(4÷4)
=50:1;
2米:4厘米
=200÷4
=50.
點(diǎn)評(píng):此題主要考查了化簡(jiǎn)比和求比值的方法,另外還要注意化簡(jiǎn)比的結(jié)果是一個(gè)比,它的前項(xiàng)和后項(xiàng)都是整數(shù),并且是互質(zhì)數(shù);而求比值的結(jié)果是一個(gè)商,可以是整數(shù)、小數(shù)或分?jǐn)?shù).