Tính:
1) ( 1998 . 1999 - 1998 . 1998 - 1000 - 98 ) : 2016
2) 2016 . 2016 - 2012 . 2020
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1) (1998.1999 - 1998.1998 - 1900 - 98) : 2016
= [1998.(1999 - 1) - 1998) : 2016
= (1998 - 1998) : 2016
= 0 : 2016
= 0
2) 2015.2015 - 2013.2017
= 20152 - (2015 - 2).(2015 + 2)
= 20152 - (20152 - 22)
= 20152 - 20152 + 4
= 4
\(=\left(1999\times1998+1998\times1997\right)\times\left(1+\dfrac{1}{2}:1\dfrac{1}{2}-1\dfrac{1}{3}\right)\)
\(=\left(1999\times1998+1998\times1997\right)\times\left(1+\dfrac{1}{2}:\dfrac{3}{2}-\dfrac{4}{3}\right)\)
\(=\left(1999\times1998+1998\times1997\right)\times\left(1+\dfrac{1}{3}-\dfrac{4}{3}\right)\)
\(=\left(1999\times1998+1998\times1997\right)\times\left(\dfrac{4}{3}-\dfrac{4}{3}\right)\)
\(=\left(1999\times1998+1998\times1997\right)\times0\)
\(=0\)
\(\left(1+2+3+...+100\right).\left(1^2+2^2+3^3+...+100^2\right).\left(65.111-13.15.37\right)\)
\(=\left(1+2+3+...+100\right).\left(1^2+2^2+3^3+...+100^2\right).\left(7215-7215\right)\)
\(=\left(1+2+3+...+100\right).\left(1^2+2^2+3^3+...+100^2\right).0\)
\(=0\)
\(1999.1999.1998-1998.1998.1999\)
\(=1999.1998.\left(1999-1998\right)\)
\(=1999.1998.1\)
Tham khảo nhé~
1) (1998.1999 - 1998.1998 - 1000 - 98) : 2016
= [1998.(1999 - 1998) - 1098) : 2016
= (1998.1 - 1098) : 2016
= (1998 - 1098) : 2016
= 900 : 2016
= \(\frac{25}{56}\)
b) 2016.2016 - 2012.2020
= 20162 - (2016 - 4).(2016 + 4)
= 20162 - (20162 - 42)
= 20162 - 20162 + 42
= 0 + 16
= 16