混合运算. ÷+÷; 27÷[(﹣)×3]; 8.5﹣(5.6+4.8)÷1.3.
估算:905500-500900≈403553-205000≈505500-408900≈703543-205050≈803033-205010≈805500-508900≈
估算:117÷2≈ 124÷2≈153÷5≈ 122÷5≈
估算:252÷2≈ 247÷2≈357÷5≈ 334÷2≈
口算:150÷6= 216÷9=272÷8= 336÷8=
口算:741÷3= 852÷2=963÷3= 123÷3=