in plain and short, is just their product.
now, let's convert the mixed fractions to "improper" firstly, and then multiply.
[tex] \bf \stackrel{mixed}{1\frac{1}{4}}\implies \cfrac{1\cdot 4+1}{4}\implies \stackrel{improper}{\cfrac{5}{4}}
\\\\\\
8\cdot 8\cdot \cfrac{5}{4}\implies \cfrac{8\cdot 8\cdot 5}{4}\implies \cfrac{320}{4}\implies 80 [/tex]
