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1、,百分数的认识,表白寺实验小学六年级(3)班期中数学成绩汇总,23.2读作:,百分之二十三点二,28.3读作:,百分之二十八点三,48.2读作:,百分之四十八点二,你在生活中见过百分数吗?,据新华社报道,地球表面陆地面积仅占29%,全球沙漠面积占地球陆地面积的近25%,而且沙漠化面积还在增加。陆地除了沙漠、冰川等土地外,只有约30%可以耕种。另据统计,目前世界上约有40%的人口严重缺水,而据我国资料显示,全国湖泊约有75%的水域已受到显著污染。自然环境的恶化也严重威胁到地球上的野生物种,如今全球12%的鸟类和25%的哺乳动物濒临灭绝,而过渡捕捞已导致30%的鱼类资源枯竭。,表白寺实小足球比赛中
2、,六(3)班获得了一次罚点球的机会,他们准备派下列三名队员中的一名去罚点球.,赵文建:曾经罚点球罚中18次.,王兵:曾经罚点球罚中7次.,朱文斌:曾经罚点球罚中21次.,你认为应该选派哪名队员?,你认为应该选派哪名队员?,赵文建:曾经罚点球20次,罚中18次,王兵:曾经罚点球10次,罚中7次.,朱文斌:曾经罚点球25次,罚中21次.,中球的次数是总次数的几分之几(中球率),这个时候大家能不能看出谁的中球率高?,如果我们把上面的三个分数化成分母为100的分数就很容易看出了!,=,=,=,=,=,=,科技小组做黄豆种子的发芽实验,天后种子的发芽情况如下表,你认为哪个品种的发芽情况最好?与同学进行交
3、流!,化成分母为100的分数就很容易比较了!,一号种子发芽率,二号种子发芽率,三号种子发芽率,=,=,=,2006年,全国各省、自治区、直辖市,上报的各类安全事故中,事故灾难占59%;社会安全事故占31%;自然灾害占10%,其中,溺水占31.25%,交通事故占19.64%,斗殴占10.71%,校园伤害占14.29%,中毒占2.68%,学生踩踏事件占1.79%,自杀占5.36%,房屋倒塌占0.89%,自然灾害占9.82%,其他意外事故占3.57%。,2006年,全国各省、自治区、直辖市,上报的各类安全事故中,事故灾难占 ;社会安全事故占 ;自然灾害占 ,其中,溺水占 ,交通事故占 ,斗殴占 ,校
4、园伤害占 ,中毒占 ,学生踩踏事件占 ,自杀占 ,房屋倒塌占 ,自然灾害占 ,其他意外事故占 。,从下面10名篮球爱好者中挑选出3名参加篮球比赛,假如你是教练,你会选谁去参加比赛?,71.2%,71.4%,72%,75%,76.9%,65%,62.5%,70%,80%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%
5、,76.9%,65%,62.5%,70%,80%,72%,64%,71.2%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,72%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,72%,64%,80%,72%,6
6、4%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,71.4%,75%,76.9%,65%,62.5%,70%,80%,71.2%,71.4%,72%,75%,76.9%,65%,62.5%,70%,80%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,6
7、5%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.2%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,72%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,8
8、0%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.2%,71.4%,72%,75%,76.9%,65%,62.5%,70%,80%,64%,72%,6
9、4%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.2%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,72%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,6
10、4%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%
11、,76.9%,65%,62.5%,70%,80%,72%,64%,71.2%,71.4%,72%,75%,76.9%,65%,62.5%,70%,80%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.2%,71.4%,75%,76.9%,65%
12、,62.5%,70%,80%,72%,64%,72%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%
13、,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.2%,71.4%,72%,75%,76.9%,65%,62.5%,70%,80%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.
14、5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.2%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,72%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,8
15、0%,72%,64%,72%,64%,80%,72%,64%,70%,80%,72%,64%,62.5%,70%,80%,72%,64%,65%,62.5%,70%,80%,72%,64%,76.9%,65%,62.5%,70%,80%,72%,64%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,71.4%,75%,76.9%,65%,62.5%,70%,80%,72%,64%,百分数的意义: 像22%、28%、90%、117.5%,这样的数叫做百分数,表示一个数是另一个数的百分之几。百分数也叫百分比、百分率。,下面的哪个分数可以用百分数表示? 1.2006年亚运会
16、中国的金牌数是金牌 总数的,2.一个苹果重,3.我国人口占世界人口的,4.一张桌面的长是,米,千克,(),(),百分数与分数在意义上的区别:分数既可以表示一个数是另一个数的几分之几,又可以表示一个具体的数量,而百分数是表示一个数是另一个数的百分之几,表示两个数比较的结果,是一个比率,百分数不能表示具体的数量,后面不带单位名称。,(2)分母是100的分数就是百分数。,(3)一根绳长75米。,(1)这批产品的合格率是98%。,判断,涂色部分占“1”的百分之几?,( ),( ),( ),( ),( ),( ),9,57,100,地球表面陆地面积仅占29%,沙漠面积占地球陆地面积的近25%,而且沙漠化面积还在增加。陆地面积中,只有约30%的土地可以耕种。 自然环境的恶化严重威胁着野生物种,如今全球12%的鸟类和25%的哺乳动物濒临灭绝,而过度捕捞已导致30%的鱼类资源枯竭。,选择合适的百分数填空 120% 100% 6% (1)由于全班同学的互相帮助,共同努力,