解:0.45=
=
=45%;
0.6=
=
=60%;
20.6%=
=
=0.206;
3.2=
=
=320%;
65%=0.65=
=
;
1
=1.2=120%;
見(jiàn)下圖:
小數(shù) | 0.45 | 0.6 | 0.206 | 3.2 | 0.65 | 1.2 |
分?jǐn)?shù) | | | | | | |
百分?jǐn)?shù) | 45% | 60% | 20.6% | 320% | 65% | 120% |
分析:(1)把分?jǐn)?shù)化百分?jǐn)?shù),先用分?jǐn)?shù)的分子除以分母得出小數(shù)商,除不盡時(shí)通常保留三位小數(shù),再把小數(shù)點(diǎn)向右移動(dòng)兩位,同時(shí)填上百分號(hào);
(2)把分?jǐn)?shù)化小數(shù),用分?jǐn)?shù)的分子除以分母即得小數(shù)商,除不盡時(shí)通常保留三位小數(shù);
(3)把百分?jǐn)?shù)化小數(shù),只要去掉百分號(hào),同時(shí)把小數(shù)點(diǎn)向左移動(dòng)兩位即可;
(4)把百分?jǐn)?shù)化分?jǐn)?shù),先寫成分?jǐn)?shù)的形式,再進(jìn)一步化簡(jiǎn)成最簡(jiǎn)分?jǐn)?shù)
(5)把小數(shù)化成百分?jǐn)?shù),只要把小數(shù)點(diǎn)向右移動(dòng)兩位,同時(shí)添上百分號(hào)即可.
(6)把小數(shù)化分?jǐn)?shù),一位小數(shù)表示十分之幾,兩位小數(shù)表示百分之幾,三位小數(shù)表示千分之幾…先寫成分?jǐn)?shù)的形式,再進(jìn)一步化簡(jiǎn)成最簡(jiǎn)分?jǐn)?shù).
點(diǎn)評(píng):此題考查百分?jǐn)?shù)、分?jǐn)?shù)與小數(shù)互化方法的靈活運(yùn)用.