百分数的认识1精5[1]ppt课件

.,欢迎各位家长莅临指导,.,数学(北师大.五年级上册),百分数的认识,.,府谷一小五（2）班期中数学成绩汇总表,.,百分之十五点七,百分之三十点四,百分之五十二点九,.,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。,.,.,.,府谷一小足球比赛中,五（2）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.,.,白展鹏：曾经罚点球罚中18次.,齐浩：曾经罚点球罚中7次.,杜强：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?,白展鹏：曾经罚点球20次，罚中18次.,齐浩：曾经罚点球10次,罚中7次.,杜强：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%,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%,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%,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%,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%,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%,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%,62.5%,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%,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%,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%,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%,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%,62.5%,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%,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%,.,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，这次考试及格率达到（）%(2)轿车的速度是客车的（）%(3)开展节约活动以来，本月学校的用电量比上月减少了（）%,100,120,6,.,百分数表示成语,百