1、西师大版二年级数学上册,重庆市云阳县 冉崇兵,8、9的乘法口诀,8条,你们知道1只 螃蟹有几条腿吗？,5只螃蟹一共有 多少条腿？,85= （元）,58= （元）,五八四十,40,40,准备题,填一填，编一编。,1只螃蟹有8条腿，8只螃蟹几条腿？ 9只呢？,填一填，编一编。,8个8得64,8864,八八六十四,9个8得72,8972,八九七十二,8只,9只,表示的意思,乘法算式,口 诀,1支钢笔9元钱， 9支钢笔多少元？,99= （元）,九九八十一,81,解决问题，编9的乘法口诀。,口诀：,计算。,98=,48,口诀：（ ）,八九七十二,99=,81,口诀：（ ）,九九八十一,一九得九,二九十八
2、,三九二十七,2、分别把9乘19的积圈起来，再找规律。,1,2,3,4,5,6,7,8,9,11,12,13,14,15,16,17,18,19,20,10,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,几乘9，积就是几十少几
3、。,积的十位上的数加上个位上的数都等于9。,2、分别把9乘19的积圈起来，再找规律。,1,2,3,4,5,6,7,8,9,11,12,13,14,15,16,17,18,19,20,10,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89
4、,90,从上往下看，积的个位上的数字依次减少1， 十位上的数字依次增加1。,1、口算。,24,56,8,48,32,16,64,40,72,2、填空。,9 =45,9=63,=72,4 =36,9 =9,5 =40,5,9,7,1,8,8,3、看算式写得数。,67,=42（个）,8盒呢？,68,=48（个）,4、口答。,7盒有多少个？,9盒呢？,69,=54（个）,5、口算。,84=,32,97=,63,28=,16,89=,72,46=,24,98=,72,82=,16,49=,36,87=,56,78-8=,48,29+9=,27,18-8=,0,6、计算。,6,8,7,5,8,48,64,56,40,6、计算。,3,6,9,7,9,27,54,81,63,7、计算。,93=,27,83=,24,29=,18,86=,48,80-59=,21,35+49=,84,77-77=,0,9+76=,85,85= （元）,40,40,8、买一组物品要多少元？,每件8元。,每件9元。,（1）,（ ）元,92= （元）,18,8、买一组物品要多少元？,每件8元。,每件9元。,（2）,（ ）元,18,84= （元）,32,8、买一组物品要多少元？,每件8元。,每件9元。,（3）,（ ）元,32,85= （个）,40,9、有多少个气球？,移动棋子，使每边都有3颗棋子。,
