三年级数学天天练试题及答案2019.2.14(速算与巧算)(2)
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2018-12-25 21:33:14
【答案】
①536+(541+464)+459
=(536+464)+(541+459)
=2000
②588+264+148
=588+(12+252)+148
=(588+12)+(252+148)
=600+400
=1000
③8996+3458+7546
=(8996+4)+(3454+7546)
=9000+11000(把3458分成4和=9000+110003454)
=20000
④567+558+562+555+563
=560×5+(7-2+2-5+3)(以560为基准数)
=2800+5=2805