342-420÷60
=342-7
=335
245+255÷30
=245+8.5
=253.5
218-178+82
=218+82-178
=300-178
=122
5×182+18×5
=5×(182+18)
=5×200
=1000
82×﹙351+104﹚
=82×455
=37310
﹙522-477﹚×140
=45×140
=6300
9090÷15×20
=9090×20÷15
=181800÷15
=12120
63×63+37×36 估计你写错数字了,否则可以简便
=3969+1332
=5301
35×9÷3
=35×3
=105