Tính nhanh 1-2-3+4+5+7+8+…+1997-1998-1999+2000+2001 1-3+5-7+…+2001-2003+2005 942-2567+2563-1942

Question

Tính nhanh
1-2-3+4+5+7+8+…+1997-1998-1999+2000+2001
1-3+5-7+…+2001-2003+2005
942-2567+2563-1942

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Delilah 3 tháng 2021-09-05T18:19:07+00:00 2 Answers 6 views 0

Answers ( )

    0
    2021-09-05T18:20:09+00:00

    Đáp án:

     

    Giải thích các bước giải:

    a. 1-2-3+4+5+7+8+…+1997-1998-1999+2000+2001

    =(1-2-3+4)+(5-7-8+9)+…+(1997-1998-1999+2000)+2001

    =0+0+…+0+2001

    =2001

    b. 1- 3+5-7+…+2001-2003+2005

     c. 942-2567+2563-1942

    =(942-1942)-(2563-2567)

    =-1000-4

    =-1004

                                                    Chúc bạn học tốt  !!!

    0
    2021-09-05T18:20:44+00:00

    $\text { Đáp án: }$

    ` 1-2-3+4+5+7+8+…+1997-1998-1999+2000+2100 `

    ` =(1-2-3+4)+(5-7-8+9)+…+(1997-1998-1999+2000)+2001 `

    ` =0+0+…+0+2001 `

    ` =2001 `

    ` 1-3+5-7+…+2001-2003+2005 `

    ` =(1-3)+(5-7)+…+(2001-2003)+2005 `

    ` =(-2)+(-2)+…+(-2)+2005 `

    ` =-2.1002+2005 `

    ` =-2004+2005 `

    ` =1 `

    ` 942-2567+2563-1942 `

    ` =(942-1942)-(2563-2567) `

    ` =-1000-4 `

    ` =-1004 `

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