人教版五年级下册第四单元分数和小数的互化第二课时ppt

1、1? ?1? ?1? ?r?al ?1a?1? ?1?1?2 0.2，0.08，1.5，2.045 ?r?al ?a?1? ? ?1? ?r?ra?1a灄漩? r?al ?a?1? ? ?1? ?r?ra.?1a?1? ?al ?a?1? ? ?1? ?a ?a?11P1?a?ra ?1?1? ?3 ?灄 ?ial?a ?灄 ?rial?a ?al?灄Br?tiib?灄 ?8?e ?aa? ?灄 ial?a ?l?t B1?a ?aaab?a ?8?e ?r ? ?l?t ?i? ?aaae ?aaal?灄 ?灄 ?aial?a ?aaaaa8 ?aaalaa灄 ?i?l Bra?aae ?灄

2、 ?rial?a ?i?b?灄 ?a?t ?abaa ?aia?abrialae ra?aai?lae. ?r?al ?a?1? ? ?1? ?r?ra4?abae ?l?:4 41 11 1 ?rerl?laae?灄:?aaba灄i?al ?a?B8iiaat ?l?灄 ?a?rl? ?a?tA?r?a ?iar?t : ?l?t: ?ae/ 1.25?bBi?a ?iar?t: ?l?t: ?ae/ ?b50.7,910, 0.25 ,43100,7251145,r? 6?aa? ?11?1?1? r1r? ?11? ?r? ?1?1.?1?1? 6?灄 ?ial?a ?灄Bi?t ?ai

3、?灄Bi?t?ial?a ?8-?aaaaa8aa ?r?e ?ra?aiaaal?a?i?t ?灄 ?ial?a ?灄 ?rial?a ?iib?灄 ?iaaal ?l?灄i?eiat.?a?i?t ?灄 ?ial?a ?灄 ?rial?a ?a?灄B?aaliib?灄 ra?aiaaal.7?Mai? 10B 100B 1000 ?t ?a?灄 ?ial?a ?灄 ?rial?a ?iib?灄 . 91043100= 0.9= 0.438 ? ?Mai 1000B100B10B. ?t ?灄 ?ial?a ?灄 ?rial?a ?alrlatBr?tiib?灄 ?M?i? ?M?i?B?a

4、aalaa灄 1?a ?ab?a ?8?e ?r 0?l?ti?t B?灄?aa?i?l ?aaab?a ?aa? ?i?t ?l ?8a8 ?ala? ?灄 ial?a ?aaaa8 ra?abe. 9? ?Mai 1000B100B10B. ?a?t ?灄 ?ial?a ?灄 ?rial?a ?r?e ?ra?aiib?灄10725=74254=28100= 0.28725= 725 = 0.28? ?r? ?aab灄:? ?Mai 1000B100B10B. ?a?t ?灄 ?ial?a ? ?Mai 1000B100B10B. ?t ?灄 ?rial?a ra?iib?灄. ?灄 ia

5、l?a ?at ?a?t ?aaalal? ?灄B?l?l?灄 ?aial?a ?aai?l ?aaa?t ?8?t ?l ?灄B?a ?aial?a ?Mai? ?aaa?t ?8?t ?l ?a.11?a灄? ?灄?灄? 灄a? ?0?1? ?0a0?0? 4?1? l? ?l? r1? ?a?1? ?r?r ?1?1?1?4?1? ?1?1? l? ?1?1?漩1? a ?a灄 P1?P1a? ?1?1?.?a灄? ?灄?灄? 灄a? ?0?1? ?0a0?0? ?a ?1?1?11145= 1145(2?1?1a灄 ?r?al ?1?1? ?1?1?.)0.2412910= 0.943

6、100= 0.43725= 0.2811450.240.240.250.280.430.70.9所以1145 0.25 72543100 0.791013 ? ?Mai 1000B100B10B. ?t ?灄 ?ial?a ?灄 ?rial?a ?alrlatBr?tiib?灄 ?M?i? ?M?i?B?aaalaa灄 1?a ?ab?a ?8?e ?r 0?l?ti?t B?灄?aa?i?l ?aaab?a ?aa? ?i?t ?l ?8a8 ?ala? ?灄 ial?a ?aaaa8 ra?abe. 14720730?aa?8 ?灄 ?rial?a ?atiib?灄 ?aa?t ?aMai

7、? ralai?灄 ?e? ?a ?aa8?aaab?a 2?at5?tBi?t ?a ?8?aaab?a ?b.?l?: ?a ?Mai? 20=225?灄 ?aa?8 ?灄 ?rial?a ra?iib?灄.i?r?灄 ?M?i? 2?at 5?aa ?t ?a ?8?aaab?a ?l?t ?aa?8 ?灄 ?rial?a ?atiiib?灄 b?t.?l? ?a ?Mai? 30=235B ?灄 ?aa?8 ?灄 ?rial?a ?atiib?灄 b?t.15432562232073017?灄 ?ial?a ?灄 ?rial?a ?iib?灄 ral?aa?l?a ?灄 ?ial?a

8、?灄 ?rial?a ral?ral?riib?灄 ?lb?e ?l灄 ?raai?e1634?1 ?漩? P1?1? ?1?1? P1?r? ?0l ?1? ? ?11? ?r1?1Pl? A?漩? ? 漩?1 ?1? ?r?1 B ?漩? 0.8 ? 漩?1 ?1? ?r?1 ?ra? ?漩? ? P? 17?r灄:1.rat ?灄 ial?a ?at ?灄 ?ial?a ?tiaaal ?a灄rB?aaaerl ?灄 ?ial?a ?灄 ?rial?a ?aaa?eBra?aiib?灄 ?l灄 ?l?t ?灄 ?aial?a ?aaai?l ?M?i? ?t.2.?灄 ?ial?a ?灄

9、 ?rial?a r?tiib?灄 B灄?r?i iat ?aa? ?灄 ial?a ?l?t ?灄 ?88? ? ?aaa灄i?r?灄Baarab ?aa? ?灄 ial?a ?l?t ?r?b ?88? ? ?a?灄Baarab aaai?lae.18A?11a灄?1?灄 ?a1?1.?1a灄漩? r?al ?a?1? ? ?1? ?r?ra.834292756524154017152（ ）（ ）（ ）（ ）0.15、1.042、2.652. ?1a灄漩? ? a?1? ?r?al ?1? ?r?ra.(?1? ?r?al ?1? ?1?ra ?a1a1r1?l?3?1?1a灄 P1?P1a? ?1?)3.?1a灄漩? ? a?1? ?1? ?r?al ?1? ?1?ra ?r?r?(?1?ra r1a1r11?r? “” ra1a1r1?l?a1?1? “” ?a1?1? ?rr.191 23 41 41 52 53 54 50.5、0.05、0.001、0.25910731009100401000 2.?aa?l?a ?灄 ?ia