A=(9/1999+99/999+999/9999).(1/5-1/4+1/20)

A=(9/1999+99/999+999/9999).(-1/20+1/20)

A=(9/1999+99/999+999/9999).0

A=0

Vì mọi số nhân vs 0 thì đều = 0 kể cả phân số

mk nhanh nhất ủng hộ nha

\(A=\left(\frac{9}{1999}+\frac{99}{999}+\frac{999}{9999}\right)\cdot0\)

A=0

Câu a :

A = 2\(\frac12\) : (- \(\frac12\))^2 - \(\frac{1}{-3}\).(\(\frac{1}{-2}\) - \(\) \(\frac43\) : \(-\frac89\))

A = \(\frac52\) : \(\frac14\) + \(\frac13\).(-\(\frac12\) + \(\frac43\times\frac98\))

A = \(\frac52\times4\) + \(\frac13\).(- \(\frac12+\frac32\))

A = \(10\) + 1/3

A = 30/3 + 1/3

A = 31/3

Câu b:

B = (3\(\frac{10}{99}\) + 4\(\frac{11}{99}\) - \(\frac{58}{229}\)).(\(\frac12\) - \(\frac43\) - \(\frac16\))

B = (7\(\frac{21}{99}\) - \(\frac{58}{229}\))(3/6 - 8/6 - 1/6)

B = (7\(\frac{7}{33}\) - \(\frac{58}{229}\)).(-1)

B = - (\(\frac{238}{33}-\frac{58}{229}\))

B = - (\(54502\)/7557 - 1914/7557)

B = - 52588/7557

\(Q=\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{999}\right)\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\text{ }\)

\(Q=\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{999}\right)\left(\frac{3}{6}-\frac{2}{6}-\frac{1}{6}\right)\)

\(Q=\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{999}\right).0\)

\(Q=0\)

Q=(1/99+12/999+123/999).(1/2-1/3-1/6) =(1/99+12/999+123/999).0 Q=0

#)Giải :

\(\left(3\frac{10}{99}+4\frac{11}{99}-5\frac{8}{299}\right).\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)

\(=\left(3\frac{10}{99}+4\frac{11}{99}-5\frac{8}{299}\right).0\)

\(=0\)

Lời giải 

=\(\left(3\frac{10}{99}+4\frac{11}{99}-5\frac{8}{299}\right).0\)

\(=0\)

Ta có :

M = \(\frac{\frac{1}{99}+\frac{2}{98}+\frac{3}{97}+...+\frac{99}{1}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)

M = \(\frac{1+\left(\frac{1}{99}+1\right)+\left(\frac{2}{98}+1\right)+\left(\frac{3}{91}+1\right)+...+\left(\frac{98}{2}+1\right)}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)

M = \(\frac{\frac{100}{100}+\frac{100}{99}+\frac{100}{98}+\frac{100}{97}+...+\frac{100}{2}}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)

M = \(\frac{100.\left(\frac{1}{100}+\frac{1}{99}+\frac{1}{98}+\frac{1}{97}+...+\frac{1}{2}\right)}{\frac{1}{2}+\frac{1}{3}+\frac{1}{4}+...+\frac{1}{100}}\)

M = \(100\)

N = \(\frac{92-\frac{1}{9}-\frac{2}{10}-\frac{3}{11}-...-\frac{92}{100}}{\frac{1}{45}+\frac{1}{50}+\frac{1}{55}+...+\frac{1}{500}}\)

N = \(\frac{\left(1-\frac{1}{9}\right)+\left(1-\frac{2}{10}\right)+\left(1-\frac{3}{11}\right)+...+\left(1-\frac{92}{100}\right)}{\frac{1}{45}+\frac{1}{50}+\frac{1}{55}+...+\frac{1}{500}}\)

N = \(\frac{\frac{8}{9}+\frac{8}{10}+\frac{8}{11}+...+\frac{8}{100}}{\frac{1}{45}+\frac{1}{50}+\frac{1}{55}+...+\frac{1}{500}}\)

N = \(\frac{8.\left(\frac{1}{9}+\frac{1}{10}+\frac{1}{11}+...+\frac{1}{100}\right)}{\frac{1}{5}.\left(\frac{1}{9}+\frac{1}{10}+\frac{1}{11}+...+\frac{1}{100}\right)}\)

N = \(40\)

\(\Rightarrow\)M : N = \(\frac{100}{40}\%=250\%\)

thiếu đề r bn

\(\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{999}\right)\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)

\(=\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{999}\right).0\)

\(=0\)

\(\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{9999}\right)\left(\frac{1}{2}-\frac{1}{3}-\frac{1}{6}\right)\)=\(\left(\frac{1}{99}+\frac{12}{999}+\frac{123}{9999}\right).0=0\)

Mk ko biết lm nhưng cứ k thoải mái nha

SORRY

Giup tui voi !!!!!!!!!!!!!!!!!!!!!!!!!!! Mai phai nop roi !!!!!!!!!!!!!!!!!!!