北师大版二年级数学上册第八单元《8.4 做个乘法表》优秀课件

1、,北师大版二年级数学上册课件,做个乘法表,课前导入,我们学完了19的乘法口诀，你能熟练的背诵出来吗？,这节课我们就来整理这单元的知识。,16,30,14,45,32,10,48,24,42,这些算式的积都是18。,把哪些算式排在一起？,这些算式乘数中都有3。,做个乘法表,探究新知,1,2,3,4,5,6,7,8,9,3,3,3,6,9,12,15,18,21,24,27,找出乘数中有3的乘法算式，并完成下表。,找出积是18的乘法算式，并填一填。,三六十八,二九十八,2,9,18,18,9,2,3,6,6,3,18,18,下面是淘气做的乘法表，你能帮他填完整吗？,12=2,13=3,14=4,1

2、5=5,16=6,17=7,18=8,19=9,21=2,23=6,8,25=10,26=12,14,28=16,29=18,31=3,32=6,33=9,34=12,15,36=18,37=21,38=24,27,41=4,42=8,43=12,44=16,45=20,24,47=28,32,49=36,51=5,52=10,53=15,54=20,25,56=30,57=35,40,59=45,61=6,62=12,18,64=24,65=30,66=36,67=42,68=48,54,71=7,14,73=21,74=28,75=35,76=42,49,78=56,79=63,8,82=

3、16,83=24,84=32,85=40,86=48,87=56,88=64,72,91=9,92=18,93=27,36,95=45,96=54,63,98=72,99=81,22=4,11=1,观察下表，你发现了什么？,12=2,13=3,14=4,15=5,16=6,17=7,18=8,19=9,21=2,23=6,8,25=10,26=12,14,28=16,29=18,31=3,32=6,33=9,34=12,15,36=18,37=21,38=24,27,41=4,42=8,43=12,44=16,45=20,24,47=28,32,49=36,51=5,52=10,53=15,5

4、4=20,25,56=30,57=35,40,59=45,61=6,62=6,18,64=24,65=30,66=36,67=42,68=48,54,71=7,14,73=21,74=28,75=35,76=42,49,78=56,79=63,8,82=16,83=24,84=32,85=40,86=48,87=56,88=64,72,91=9,92=18,93=27,36,95=45,96=54,63,98=72,99=81,横着看，每一行都是相同个数增加的。,是几的口诀,它们的积就依次相差几。,12=2,13=3,14=3,15=5,16=6,17=7,18=8,19=9,21=2,23=

5、6,8,25=10,26=12,14,28=16,29=18,31=3,32=6,33=6,34=12,15,36=18,37=21,38=24,27,41=4,42=8,43=12,44=16,45=20,24,47=28,32,49=36,51=5,52=10,53=15,54=20,25,56=30,57=35,40,59=45,61=6,62=6,18,64=24,65=30,66=36,67=42,68=48,54,71=7,14,73=21,74=28,75=35,76=42,49,78=56,79=63,8,82=16,83=24,84=32,85=40,86=48,87=56,

6、88=64,72,91=9,92=18,93=27,36,95=45,96=54,63,98=72,99=81,竖着看，第几列就用几开头。,12=2,13=3,14=3,15=5,16=6,17=7,18=8,19=9,21=2,23=6,8,25=10,26=12,14,28=16,29=18,31=3,32=6,33=6,34=12,15,36=18,37=21,38=24,27,41=4,42=8,43=12,44=16,45=20,24,47=28,32,49=36,51=5,52=10,53=15,54=20,25,56=30,57=35,40,59=45,61=6,62=6,18,

7、64=24,65=30,66=36,67=42,68=48,54,71=7,14,73=21,74=28,75=35,76=42,49,78=56,79=63,8,82=16,83=24,84=32,85=40,86=48,87=56,88=64,72,91=9,92=18,93=27,36,95=45,96=54,63,98=72,99=81,斜着看，乘数相同的算式成一条直线。,12=2,13=3,14=3,15=5,16=6,17=7,18=8,19=9,21=2,23=6,8,25=10,26=12,14,28=16,29=18,31=3,32=6,33=6,34=12,15,36=18

8、,37=21,38=24,27,41=4,42=8,43=12,44=16,45=20,24,47=28,32,49=36,51=5,52=10,53=15,54=20,25,56=30,57=35,40,59=45,61=6,62=6,18,64=24,65=30,66=36,67=42,68=48,54,71=7,14,73=21,74=28,75=35,76=42,49,78=56,79=63,8,82=16,83=24,84=32,85=40,86=48,87=56,88=64,72,91=9,92=18,93=27,36,95=45,96=54,63,98=72,99=81,交换乘数

9、的位置积是相同的。,课堂练习,把乘法口诀填完整。,二十一,四十五,六十三,五十六,三十六,三十五,六十四,二十四,3,6,18,根据乘法口诀“三六十八”能选3,6和18。,18,3,6,3,18,18,6,3,从“18,27,3,9,6”中选出几个数，组成两道乘法算式和两道除法算式。,6,3,9,27,根据乘法口诀“三九二十七”可以选3,9和27。,27,3,9,3,27,27,9,3,从“18,27,3,9,6”中选出几个数，组成两道乘法算式和两道除法算式。,9,八五折,58=,五八四十,40（人）,答：座位够了。,座位够吗？,一张桌子能坐8个人。,4035,八五折,想一想，算一算。,6,八五折,想一想，算一算。,7,算一算,10,69= 45= 41= 25=,88= 74= 19= 27=,44= 66= 87= 48=,99= 22= 67= 6+7=,54,16,36,56,32,20,4,64,28,9,14,81,4,42,13,4,5,6,7,8,9,4,8,