(1/12+1/13-1/2012):(1/13+1/12-1/2012+1/12.13.2012)+1:(25.2012-155)
Giúp mk lun nha
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(a,\left(1-\dfrac{1}{10}\right)\times\left(1-\dfrac{1}{11}\right)\times\left(1-\dfrac{1}{12}\right)\times\left(1-\dfrac{1}{13}\right)\times\left(1-\dfrac{1}{14}\right)\times\left(1-\dfrac{1}{15}\right)=\dfrac{9}{10}\times\dfrac{10}{11}\times\dfrac{11}{12}\times\dfrac{12}{13}\times\dfrac{13}{14}\times\dfrac{14}{15}=\dfrac{9}{15}=\dfrac{3}{5}\)
\(b,\dfrac{2013\times2012-2}{2011+2011\times2013}=\dfrac{\left(2014-1\right)\times2012-2}{2011\times\left(2013+1\right)}=\dfrac{2014\times2012-2012-2}{2011\times2014}=\dfrac{2014\times2012-2014}{2011\times2014}=\dfrac{2014\times\left(2012-1\right)}{2011\times2014}=\dfrac{2011\times2014}{2011\times2014}=1\)
1 tính
a 100 + (+430) + 2145 + (-530)
b (-12) . 15
c (+12) . 13 + 13 . (-22)
d {[ 14 : (-2)] + 7} : 2012
\(a,100+\left(+430\right)+2145+\left(-530\right)\)
\(=100+430+2145-530\)
\(=\left(100+2145\right)+\left(430-530\right)\)
\(=2245+\left(-100\right)\)
\(=2245-100\)
\(=2145\)
\(b,,\left(-12\right).15\)
\(=-180\)
\(c,\left(+12\right).13+13.\left(-22\right)\)
\(=13.\left[12-22\right]\)
\(=13.\left(-10\right)\)
\(=-130\)
\(d.\left\{\left[14:\left(-2\right)\right]+7\right\}:2012\)
\(=\left\{-7+7\right\}:2012\)
\(=0:2012\)
\(=0\)
g: \(B=\dfrac{1}{2}\cdot\dfrac{2}{3}\cdot...\cdot\dfrac{19}{20}=\dfrac{1}{20}\)
h: \(=\dfrac{3}{2}\cdot\dfrac{4}{3}\cdot..\cdot\dfrac{100}{99}=\dfrac{100}{2}=50\)
f: \(A=1+\dfrac{1}{2^{2014}}\)
\(B=\dfrac{2^{2014}+1+1}{2^{2014}+1}=1+\dfrac{1}{2^{2014}+1}\)
mà \(2^{2014}< 2^{2014}+1\)
nên A>B