Trả lời:
a, \(A=5\times\left(\frac{1}{5}+\frac{1}{7}\right)-\left(\frac{2}{5}+\frac{2}{17}+\frac{6}{10}+\frac{9}{51}\right)\)
\(A=5\times\left(\frac{1}{5}+\frac{1}{7}\right)-\left(\frac{2}{5}+\frac{2}{17}+\frac{3}{5}+\frac{3}{17}\right)\)
\(A=5\times\left(\frac{1}{5}+\frac{1}{7}\right)-\left(\frac{5}{5}+\frac{5}{17}\right)\)
\(A=5\times\left(\frac{1}{5}+\frac{1}{7}\right)-5\times\left(\frac{1}{5}+\frac{1}{17}\right)\)
\(A=5\times\left(\frac{1}{5}+\frac{1}{7}-\frac{1}{5}-\frac{1}{7}\right)\)
\(A=5\times\left(\frac{1}{7}-\frac{1}{17}\right)\)
\(A=5\times\frac{10}{119}\)
\(A=\frac{50}{119}\)
b, \(B=\frac{2003\times14+1988+2001\times2002}{2002+2002\times503+504\times2002}\)
\(B=\frac{\left(2002+1\right)\times14+1988+2001\times2002}{2002\times\left(1+503+504\right)}\)
\(B=\frac{2002\times14+14+1988+2001\times2002}{2002\times1008}\)
\(B=\frac{2002\times14+2002+2001\times2002}{2002\times1008}\)
\(B=\frac{2002\times\left(14+1+2001\right)}{2002\times1008}\)
\(B=\frac{2002\times2016}{2002\times1008}\)
\(B=2\)
c, Sửa dề
\(\left(4,58\div3,27+5,23\div3,27\right)\times4,08-4,08\)
\(=\left[\left(4,58+5,23\right)\div3,27\right]\times4,08-4,08\)
\(=\left(9,81\div3,27\right)\times4,08-4,08\)
\(=3\times4,08-4,08\)
\(=4,08\times\left(3-1\right)\)
\(=4,08\times2\)
\(=8,16\)
d, \(\frac{6}{11}+\frac{7}{17}+\frac{8}{25}+\frac{10}{17}+\frac{16}{11}+\frac{17}{25}\)
\(=\left(\frac{6}{11}+\frac{16}{11}\right)+\left(\frac{7}{17}+\frac{10}{17}\right)+\left(\frac{8}{25}+\frac{17}{25}\right)\)
\(=2+1+1\)
\(=4\)
