a) \(\dfrac{37}{40}-0,64\\ =\dfrac{37}{40}-\dfrac{16}{25}\\ =\dfrac{185}{200}-\dfrac{128}{200}\\ =\dfrac{57}{200}\)
b) \(130\dfrac{25}{28}-120\dfrac{12}{35}\\ =\dfrac{3665}{28}-\dfrac{4212}{35}\\ =\dfrac{18325}{140}-\dfrac{16848}{140}\\ =\dfrac{211}{20}\)
\(1-\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{1}{6}\\ =\dfrac{6}{6}-\dfrac{3}{6}-\dfrac{2}{6}-\dfrac{1}{6}\\ =\dfrac{0}{6}\\ =0\)
d) \(\dfrac{17}{8}-\dfrac{11}{6}+\dfrac{2}{9}\\ =\dfrac{153}{72}-\dfrac{132}{72}+\dfrac{16}{72}\\ =\dfrac{37}{72}\)
e) \(\dfrac{21}{28}-\dfrac{18}{60}+\dfrac{3}{5}\\ =\dfrac{3}{4}-\dfrac{3}{10}+\dfrac{3}{5}\\ \dfrac{15}{20}-\dfrac{6}{20}+\dfrac{12}{20}\\ =\dfrac{21}{20}\)