35*14-70+30怎样简便怎样算?

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35*14-70+30怎样简便怎样算?

35*14-70+30怎样简便怎样算?
35*14-70+30怎样简便怎样算?

35*14-70+30怎样简便怎样算?
=70*7-40
=490-40
=450

=(7*5*7*2)—40
=(7*7)*(2*5)—40
=49*10—40
=490—40
=450

70(7-1)+30
=70*6+30
=420+30
=450