27×21+27×78+27 299×25 34× - 知识问答

27×21+27×78+27 299×25 34×99+34 596-48+52 简便怎么做?

2个回答

27×21+27×78+27
=27×(21+78+1)
=27×100
=2700
299×25
=(300-1)×25
=300×25-25
=7500-25
=7475
34×99+34
=34×(99+1)
=34×100
=3400
596-48+52
=596+(52-48)
=596+4
=600

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