估算.(1)1602÷39 (2)396×41 (3)41863÷69(4)598÷61 (5)308×97 (6)4512÷501.
6-5= 7-4= 7-6 =10-8= 10-3= 5-3=
8-2= 8-6= 8-5=8-3= 5-4= 5-1=
10-3= 10-2= 5-2= 7-3= 6-4= 8-4=
5-5= 6-1= 7-3=8-5= 4-2= 9-7=