237+238+239+240+241+242+243=________×________=________.
网友回答
240 7 1680
解析分析:根据题意,一共7个数,中间一个是240,237比240少3,而243比240多3,这两个数结合正好是2个240,同理238+242=240×2,239+241=240×2,然后再进一步解答.
解答:
237+238+239+240+241+242+243,
=(237+243)+(238+242)+(239+241)+240,
=240×2+240×2+240×2+240,
=240×(2+2+2+1),
=240×7,
=1680.
故