三年级数学天天练试题及答案2019.2.18(速算与巧算)(2)
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2018-12-25 21:36:36
【答案】
①537-(543-163)-57
=537-543+163-57
=(537+163)-(543+57)
=700-600
=100
②947+(372-447)-572
=947+372-447-572
=(947-447)-(572-372)
=500-200
=300