(共15张PPT)
北师大版1年级上册第三单元
做个减法表
看谁算得又对又快。
4-0= 5-2= 3-0= 8-0=
8-5= 6-2= 6-5= 6-1=
7-5= 9-4=
4
4
3
1
3
5
8
2
3
5
做个减法表
你能找出6减几的算式并排一排吗?
6-6=
6-0=
6-5=
6-1=
6-4=
6-2=
6-3=
6-3=
或
6-2=
6-4=
6-1=
6-5=
6-0=
6-6=
说一说,你们是怎样排列的。
6-6=
6-0=
6-5=
6-1=
6-4=
6-2=
6-3=
6-3=
或
6-2=
6-4=
6-1=
6-5=
6-0=
6-6=
按照减号后面的数从大到小的顺序排列。
按照减号后面的数从小到大的顺序排列。
你能找出得数是8的减法算式吗?排一排。
10-2=
8-0=
9-1=
9-1=
8-0=
10-2=
或
下面是笑笑做的减法表,你能帮她填完整吗?
0
10-10
1
2
6-6
2-2
3
4
5
6
7
8
9
10
10-9
10-6
10-1
10-0
9-0
9-3
8-2
7-1
6-0
5-1
4-0
5-4
2-1
4-2
3-1
3-0
1-0
6-4
9-7
8-5
7-4
6-3
0
10-10
1
2
6-6
2-2
3
4
5
6
7
8
9
10
10-9
10-6
10-1
10-0
9-0
9-3
8-2
7-1
6-0
5-1
4-0
5-4
2-1
4-2
3-1
3-0
1-0
6-4
9-7
8-5
7-4
6-3
9-9
8-8
7-7
5-5
4-4
3-3
1-1
0-0
6-5
9-8
8-7
7-6
4-3
3-2
10-8
8-6
7-5
5-3
2-0
10-7
9-6
5-2
4-1
6-2
9-5
8-4
7-3
6-1
10-5
9-4
8-3
7-2
5-0
10-4
10-3
9-2
8-1
7-0
10-2
9-1
8-0
横着看,竖着看,斜着看,你发现了什么规律?
0
10-10
1
2
6-6
2-2
3
4
5
6
7
8
9
10
10-9
10-6
10-1
10-0
9-0
9-3
8-2
7-1
6-0
5-1
4-0
5-4
2-1
4-2
3-1
3-0
1-0
6-4
9-7
8-5
7-4
6-3
9-9
8-8
7-7
5-5
4-4
3-3
1-1
0-0
6-5
9-8
8-7
7-6
4-3
3-2
10-8
8-6
7-5
5-3
2-0
10-7
9-6
5-2
4-1
6-2
9-5
8-4
7-3
6-1
10-5
9-4
8-3
7-2
5-0
10-4
10-3
9-2
8-1
7-0
10-2
9-1
8-0
横着看,从左到右
减号前面的数相同,
减号后面的数依次减少1,
得数依次增加1。
0
10-10
1
2
6-6
2-2
3
4
5
6
7
8
9
10
10-9
10-6
10-1
10-0
9-0
9-3
8-2
7-1
6-0
5-1
4-0
5-4
2-1
4-2
3-1
3-0
1-0
6-4
9-7
8-5
7-4
6-3
9-9
8-8
7-7
5-5
4-4
3-3
1-1
0-0
6-5
9-8
8-7
7-6
4-3
3-2
10-8
8-6
7-5
5-3
2-0
10-7
9-6
5-2
4-1
6-2
9-5
8-4
7-3
6-1
10-5
9-4
8-3
7-2
5-0
10-4
10-3
9-2
8-1
7-0
10-2
9-1
8-0
竖着看,从上到下
减号前面的数依次减少1,
减号后面的数依次减少1
得数不变。
0
10-10
1
2
6-6
2-2
3
4
5
6
7
8
9
10
10-9
10-6
10-1
10-0
9-0
9-3
8-2
7-1
6-0
5-1
4-0
5-4
2-1
4-2
3-1
3-0
1-0
6-4
9-7
8-5
7-4
6-3
9-9
8-8
7-7
5-5
4-4
3-3
1-1
0-0
6-5
9-8
8-7
7-6
4-3
3-2
10-8
8-6
7-5
5-3
2-0
10-7
9-6
5-2
4-1
6-2
9-5
8-4
7-3
6-1
10-5
9-4
8-3
7-2
5-0
10-4
10-3
9-2
8-1
7-0
10-2
9-1
8-0
斜着看,从右上到左下
减号后面的数不变,
减号前面的数依次减少1,
得数依次减少1。
10以内数的减法,按得数以及算式里面的数分类后做成的减法表,无论横着看、竖着看,还是斜着看,都是有规律可循的。
这节课你们都学会了哪些知识?
你会填吗?
0
1
2
3
4
5
6
7
8
9
10
10-10
9-9
8-8
7-7
6-6
5-5
4-4
3-3
2-2
1-1
0-0
10-9
9-8
8-7
7-6
6-5
5-4
4-3
3-2
2-1
1-0
10-8
9-7
8-6
7-5
6-4
5-3
4-2
3-1
2-0
10-7
9-6
8-5
7-4
6-3
5-2
4-1
3-0
10-6
9-5
8-4
7-3
6-2
5-1
4-0
10-5
9-4
8-3
7-2
6-1
5-0
10-4
9-3
8-2
7-1
6-0
10-3
9-2
8-1
7-0
10-2
9-1
8-0
10-1
9-0
10-0
竖着填
0
1
2
3
4
5
6
7
8
9
10
10-10
9-9
8-8
7-7
6-6
5-5
4-4
3-3
2-2
1-1
0-0
10-9
9-8
8-7
7-6
6-5
5-4
4-3
3-2
2-1
1-0
10-8
9-7
8-6
7-5
6-4
5-3
4-2
3-1
2-0
10-7
9-6
8-5
7-4
6-3
5-2
4-1
3-0
10-6
9-5
8-4
7-3
6-2
5-1
4-0
10-5
9-4
8-3
7-2
6-1
5-0
10-4
9-3
8-2
7-1
6-0
10-3
9-2
8-1
7-0
10-2
9-1
8-0
10-1
9-0
10-0
斜着填
0
1
2
3
4
5
6
7
8
9
10
10-10
9-9
8-8
7-7
6-6
5-5
4-4
3-3
2-2
1-1
0-0
10-9
9-8
8-7
7-6
6-5
5-4
4-3
3-2
2-1
1-0
10-8
9-7
8-6
7-5
6-4
5-3
4-2
3-1
2-0
10-7
9-6
8-5
7-4
6-3
5-2
4-1
3-0
10-6
9-5
8-4
7-3
6-2
5-1
4-0
10-5
9-4
8-3
7-2
6-1
5-0
10-4
9-3
8-2
7-1
6-0
10-3
9-2
8-1
7-0
10-2
9-1
8-0
10-1
9-0
10-0