[tex]\bf A = \dfrac{1}{2} \cdot \dfrac{2}{3} \cdot \dfrac{3}{5}[/tex]
[tex]\bf A = \dfrac{1}{\not2} \cdot \dfrac{\not2}{\not3} \cdot \dfrac{\not3}{5}[/tex]
[tex]\bf A = \dfrac{1}{1} \cdot \dfrac{1}{1} \cdot \dfrac{1}{5}[/tex]
[tex]\boxed{\bf A = \dfrac{1}{5}}[/tex]
[tex]\bf B = \dfrac{3}{7} \cdot \Big(-\dfrac{21}{8}\Big) \cdot \dfrac{3}{9}[/tex]
[tex]\bf B = \dfrac{\not3}{\not7} \cdot \Big(-\dfrac{\not21}{\not8}\Big) \cdot \dfrac{\not3}{\not9}[/tex]
[tex]\bf B = \dfrac{1}{1} \cdot \Big(-\dfrac{3}{2}\Big) \cdot \dfrac{1}{3}[/tex]
[tex]\bf B = -\dfrac{\not3}{2} \cdot \dfrac{1}{\not3}[/tex]
[tex]\boxed{{\bf B = -\dfrac{1}{2}}}[/tex]
[tex]\bf C = \Big( -\dfrac{7}{18}\Big) \cdot \Big(-\dfrac{15}{14}\Big) \cdot \dfrac{4}{5} \cdot 6[/tex]
[tex]\bf C =\dfrac{\not7}{\not18} \cdot \dfrac{\not15}{\not14} \cdot \dfrac{4}{\not5} \cdot 6[/tex]
[tex]\bf C =\dfrac{1}{6} \cdot \dfrac{1}{2} \cdot \dfrac{4}{1} \cdot 6[/tex]
[tex]\bf C =\dfrac{1}{\not6} \cdot \dfrac{1}{\not2} \cdot \dfrac{\not4}{1} \cdot \not6[/tex]
[tex]\bf C =\dfrac{1}{1} \cdot \dfrac{1}{1} \cdot \dfrac{2}{1} \cdot 1[/tex]
[tex]\boxed{\bf C = 2}[/tex]
[tex]\bf D = \dfrac{11}{60}\cdot \Big( -\dfrac{18}{7}\Big) \cdot \Big(-\dfrac{10}{99}\Big) \cdot (-21)[/tex]
[tex]\bf D = - \dfrac{11}{60}\cdot \dfrac{18}{7} \cdot \dfrac{10}{99} \cdot 21[/tex]
[tex]\bf D = - \dfrac{11}{\not60}\cdot \dfrac{\not18}{7} \cdot \dfrac{10}{\not99} \cdot \not21[/tex]
[tex]\bf D = - \dfrac{\not11}{\not10}\cdot \dfrac{1}{\not7} \cdot \dfrac{\not10}{\not11} \cdot \not7[/tex]
[tex]\boxed{\bf D= -1}[/tex]
