《小数点移动》PPT课件.ppt
,小数点移动,双龙湾镇龙驹小学,0.009米=9毫米,0.09米,0.9米,9米,=90毫米,=900毫米,=9000毫米,从上往下观察,小数点向右,移动一位,原数就扩大到原数的10倍;,移动两位,原数就扩大到原数的100倍;,移动三位,原数就扩大到原数的1000倍;,0.009米=9毫米,0.09米,0.9米,9米,=90毫米,=900毫米,=9000毫米,从下往上观察,小数点向左,四句歌:,右移扩大、左移缩小;,移动一( 二、 三、-)位 是 10(100、1000-)倍;,位数不够“0”补位。,小数点移动要记牢;,填 空:,1、把2.3的小数点向右移动一位, 原数就( )了( )倍,2、把0.375扩大100倍,小数点 向( )移动( )位。,3、把0.73的小数点向( )移动 ( )位,原数缩小100倍。,4、把30的小数点向( )移动( )位,原数变成0.03。,扩大,10,右,二,左,二,左,三,下面的题目你会算吗?,0.20810=0.208100=0.2081000=,2.08,20.8,208,70.06,700.6,7006,7.00610=7.006100=7.0061000=,在括号里填上合适的数,并说说你是怎样想的?,8.009( )=80.09 0.07( )=70.008( )=0.08 0.036( )=36,10,10,100,1000,在下表的空格里填上正确的数.,10.75,0.36,35.4,4,107.5,3.6,354,40,1075,36,3540,400,下面的数去掉小数点,各是原数的多少倍?,(10倍),(100倍),(100倍),(1000倍),(100倍),智,力,擂,台,19,190,1900,2.36,0.236,0.0236,7,10,25,100,6,1000,506,1000,24,10,0.368,100,541,10,7295,10,1286,1000,右,三,扩大,1000,左,三,缩小,1000,78,35.28扩大十倍,选择正确的答案。,3.528,352.8,0.3528,3528,0.03528,35280,35.28缩小十倍,35.28缩小一千倍,35.28扩大一百倍,闯关,45100= 0.021000= 578.6100=901000= 9.231000= 58001000=56100= 0.054100= 0.6710=,直接写出得数,4500,20,5.78,0.09,9230,0.58,0.56,5.4,0.67,第一关,0.56= 5.6 0.407= 0.0407 740= 7.4 0.008 = 80,在圆圈里添上乘号和除号,在里填上适当的数,10,10,100,10000,第二关,1.把5.23的小数点向( )移动( )位得523,这样5.23就( ) 2.把10.2的小数点向( )移动( )位,得0.0102,这样0.0102就( ) 3.把9.4扩大到原数的( )倍是940,把9.4缩小为原数的( )是0.094 4.把( )扩大到100倍是580,把( )缩小为原数的1/100是0.0013,填空,第三关,右,两,扩大到它的100倍,左,三,缩小到它的,100,5.8,0.13,126,126,大家好,我是小数点,别看我个子小,本领却大极了,只要我动一动,要那些数变大就大,变小就小。,