I hope this is the expression you want to write:
[tex] (21)(-4)(3)(\frac{1}{5})(5) (\frac{1}{5}) [/tex]
At first we can convert all the integers in fraction form. So,
[tex] (\frac{21}{1})(-\frac{4}{1})(\frac{3}{1})(\frac{1}{5})(\frac{5}{1}) (\frac{1}{5}) [/tex]
Next step is to multiply the numerators and denominators. So,
[tex] \frac{21*(-4)*3*1*5*1}{1*1*1*5*1*5} [/tex]
=-[tex] \frac{1260}{25} [/tex]
=-[tex] \frac{252}{5} [/tex]