TINH NHANH : \(\frac{2004\times2007+6}{2005\times2005+2009}=?\)
Tính nhanh giá trị của biểu thức :
\(\frac{2004\times2007+6}{2005\times2005+2009}\)
\(\frac{2004\times2007+6}{2005\times2005+2009}\)
\(=\frac{2004\times2007-2007+6}{2005\times2005+2009}\)
\(=\frac{2005\times2005+2005+2005-2007+6}{2005\times2005+2009}\)
\(=\frac{2005\times2005+2009}{2005\times2005+2009}=1\)
tính bằng cách hợp lí :
\(\frac{1}{2001\times2003}+\frac{1}{2003\times2005}+\frac{1}{2005\times2007}+.....+\frac{1}{2009\times2011}+\frac{1}{2011\times2013}\)
Ta có: 1/ 2001 . 2003 = 1/2001 - 1/2003...
=> 1/2001 - 1/2003 + 1/2003 - 1/2005 + 1/2005 - 1/2007 + ... +1/2009 - 1/2011 +1/2011 - 1/2013
= 1/2001 - 1/2013
= 4/ 1342671
\(\frac{1}{2001\times2003}\)+\(\frac{1}{2003\times2005}\)+\(\frac{1}{2005\times2007}\)+........+\(\frac{1}{2009\times2011}\)+\(\frac{1}{2011\times2013}\)
=\(\frac{1}{2001}-\frac{1}{2003}+\frac{1}{2003}-\frac{1}{2005}+\frac{1}{2005}-\frac{1}{2007}\)+........+\(\frac{1}{2009}\)-\(\frac{1}{2011}+\frac{1}{2011}-\frac{1}{2013}\)
=\(\frac{1}{2001}\)-\(\frac{1}{2013}\)
=\(\frac{2013}{4028013}-\frac{2001}{4028013}\)=\(\frac{2}{4028013}\)
Tính giá trị của BT:
P=\(\frac{\left(2004^2\times2014+31\times2005-1\right)\left(2004\times2009+4\right)}{2005\times2006\times2007\times2008\times2009}\)
Mog các pn ghi cả cách giải cho mk
Tính nhanh:
\(\frac{2005\times2004-1}{2003\times2005+2004}\)
\(\frac{2005\cdot2004-1}{2003\cdot2005+2004}\)
\(=\frac{2005\cdot\left(2003+1\right)-1}{2003\cdot2005+2004}\)
\(=\frac{2005\cdot2003+2005-1}{2003\cdot2005+2004}\)
\(=\frac{2005\cdot2003+2004}{2003\cdot2005+2004}\)
\(=1\)
2005 x 2004 - 1 / 2003 × 2005 + 2004
= 2005 × (2003 + 1) - 1 / 2003 × 2005 + 2004
= 2005 × 2003 + (2005 - 1) / 2003 × 2005 + 2004
= 2005 × 2003 + 2004 / 2003 × 2005 + 2004
= 1
\(\frac{2005\times2004-1}{2003\times2005+2004}\)
\(=\frac{2005\times\left(2003+1\right)-1}{2003\times2005+2004}\)
\(=\frac{2005\times2003+\left(2005-1\right)}{2003\times2005+2004}\)
\(=\frac{2005\times2003+2004}{2003\times2005+2004}\)
Tính nhanh :
\(\frac{2005\times2004-1}{2003\times2005+2004}\)
\(\frac{2005x2004-1}{2003x2005+2004}\)=\(\frac{4018019}{4018019}\)= 1
Bài giải
\(\frac{2005\text{ x }2004-1}{2003\text{ x }2005+2004}=\frac{2005\text{ x }2004-1}{2003\text{ x }2005+2005-1}=\frac{2005\text{ x }2004-1}{2005\text{ x }2004-1}=1\)
\(\frac{2005\times2004-1}{2003\times2005+2004}\)\(=\)\(\frac{2005\times\left(2003+1\right)-1}{2003\times2005+2004}\)\(=\)\(\frac{2005\times2003+2005-1}{2003\times2005+20042}\)\(=\)\(\frac{2005\times2003+2004}{2003\times2005+2004}\)\(=\)1
\(\frac{2005\times2007-1}{2004+2005\times2006}\)=?
\(=\frac{2005\times\left(2006+1\right)-1}{2004+2005\times2006}=\frac{2005\times2006+2005\times1-1}{2004+2005\times2006}=\frac{2005\times2006+2004}{2004+2005\times2006}=1\)
\(\dfrac{2004\cdot2007+6}{2005\cdot2005+2009}\)
Tinh nhanh gium minh nha !
\(\dfrac{2004\cdot2007+6}{2005\cdot2005+2009}=\dfrac{2004\cdot2005+2004\cdot2+6}{2005\cdot2004+2005+2009}\\ =\dfrac{2004\cdot2005+4014}{2004\cdot2005+4014}=1\)
\(\frac{2005\times2004-1}{2003\times2005+2004}=?\)
\(\frac{2005\times2004-1}{2003\times2005+2004}=\frac{2005\times2003+2005-1}{2003\times2005+2004}=\frac{2005\times2003+2004}{2003\times2005+2004}=1\)
Tính nhanh 2004*2007+6/2005*2005+2009
Tham khảo
Ta có:
2004×2007+6
=(2005-1)×2007+6
=2005×2007-2007+6
=2005×(2005+2)-2007+6
=2005×2005+2005×2-2007+6
=2005×2005+4010-2007+6
=2005×2005+9
Vậy 2004×2007+6/2005×2005+2009=1
\(=4022028+6+2009\)
\(=4022034+2099\)
\(=4024043\)
\(\dfrac{2004\text{×}2007+6}{2005\text{×}2005+2009}\)
\(=\dfrac{\left(2005-1\right)\text{×}2007+6}{2005\text{×}2005+2009}\)
\(=\dfrac{2005\text{×}2007-2007+6}{2005\text{×}2005+2009}\)
\(=\dfrac{2005\text{×}\left(2005+2\right)-2007+6}{2005\text{×}2005+2009}\)
\(=\dfrac{2005\text{×}2005+2005\text{×}2-2007+6}{2005\text{×}2005+2009}\)
\(=\dfrac{2005\text{×}2005+2009}{2005\text{×}2005+2009}=1\)
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