竖式小学生三五档九档十三行计数器小数教学数学教具演示教师计算
¥10
72
¥2.8
12
¥13
900
¥50
600
¥11
0
¥6.8
1000
¥9.7
200
¥42.7
1
¥4.3
10
¥9.8
2000