①423÷71≈
②138÷18≈
③791÷41≈
④239÷79≈
⑤563÷82≈
⑥719÷88≈
=400+193-3
=593-3
=590
=645-(378+22)
=645-400
=245
0.56÷0.8= = = =
5×( )= 30×= 0.53= 3﹣=