数学北师大版一年级下册生活中数花生.ppt

,生活中的数,数花生,朱砂镇安莪小学朱著熙,花生生长的时候,这就是花生收获的时候,1,十七、十八、十九后面是（）,八十七、八十八、八十九后面是（）,二十,九十,我们都要努力,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,一个一个地数,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,两个两个地数,两个两个地数，数出36个花生,24681012141618202224262830323436,也可以这么数三个三个地数,三,六,九,十五,十二,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,五个五个地数,三个三个地数，数出60个花生,3691215182124273033363942454851545760,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,十个十个地数,1009080706050403020100,你会倒着数数吗？请十个十个地数，从100倒数到0。,1,2,3,4,5,6,7,8,9,10,20,30,29,28,27,19,18,17,16,15,14,13,12,11,21,22,23,24,25,26,31,32,33,34,35,36,也可以这么数五个五个地数,五,十,十五,二十五,二十,三十,三十五,四十,四十五,五十,五十五,六十五,六十,七十,七十五,八十,九十,八十,七十,六十,五十,四十,三十,二十,一十,二十二,三十二,四十二,五十二,六十二,七十二,八十二,九十二,一百零二,一百一十二,一百二十二,一百三十二,一百四十二,二十三,五十六,七十七,八十九,九十五,二十四,二十五,二十六,二十七,二十八,五十七,五十八,五十九,六十一,六十二,七十八,七十九,八十,八十一,八十二,九十,九十一,九十二,九十三,九十四,九十六,九十七,九十八,九十九,一百,考考你,说一说,二十五，三十，三十五三十二，三十四，三十六九十、八十、七十,25,30,35,40,45,32,34,36,38,90,80,70,60,60,小朋友能用几种方法数出到底有几个同学准备参加比赛呀？,1,2,8,4,3,7,5,6,2,4,6,8,当然，我们还可以这样数.,小朋友我们生活中很多事情都需要这么数一数，你想到了吗？,一个足球队的上场队员是11人，那