题目内容
102+104+108+116+132-101-103-109-127=
122
122
.分析:解法一,算式中各个加数及各个减数除了整百的数后余下数都是按倍数递加的,由此可先算整百的数,然后再据分配律计算余下的数;解法二:可将102+104+108+116+132分解为101+1+103+1+109-1+1+127+5+116进行巧算.
解答:解:
解法一:102+104+108+116+132-101-103-109-127,
=[100×5+2×(1+2+4+8+16)]-[100×4+3×(1+3+9)+1],
=[500+62]-[400+40],
=(500-400)+(62-40),
=122.
解法二:102+104+108+116+132-101-103-109-127
=101+1+103+1+109-1+127+5+116-101-103-109-127,
=1+1-1+5+116,
=122.
故答案为:122
解法一:102+104+108+116+132-101-103-109-127,
=[100×5+2×(1+2+4+8+16)]-[100×4+3×(1+3+9)+1],
=[500+62]-[400+40],
=(500-400)+(62-40),
=122.
解法二:102+104+108+116+132-101-103-109-127
=101+1+103+1+109-1+127+5+116-101-103-109-127,
=1+1-1+5+116,
=122.
故答案为:122
点评:完成本题要认真分析试中数据,根据式中数据的特点进行巧算.
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