6．比4.5大比4.9小的小数有（ ）
| A． | 5个 | B． | 3个 | C． | 无数个 |
4．用竖式计算，其中带*的要验算．
| 639+192= | 63÷8= | 635+289= |
| 700-526= | 55÷7= | *904-569= |
2．笔算下面各题
0 159723 159731 159737 159741 159747 159749 159753 159759 159761 159767 159773 159777 159779 159783 159789 159791 159797 159801 159803 159807 159809 159813 159815 159817 159818 159819 159821 159822 159823 159825 159827 159831 159833 159837 159839 159843 159849 159851 159857 159861 159863 159867 159873 159879 159881 159887 159891 159893 159899 159903 159909 159917 199269
| 45÷7= | 28÷3= | 33÷8= |
| 52÷6= | 64÷9= | 34÷5= |