Take your last item and get into usable format remember 8 = 8/1 so 2 3/4 change your problem to look like this : 8/1 * 11/4 = X or 8 X 11/4 do mulpication first and divide by denominator 4. Remember denominators are multiplied also.
$$\left({\frac{{\mathtt{8}}}{{\mathtt{1}}}}\right){\mathtt{\,\times\,}}\left({\frac{{\mathtt{11}}}{{\mathtt{4}}}}\right) = {\mathtt{22}}$$ or $$\left({\frac{{\mathtt{32}}}{{\mathtt{4}}}}\right){\mathtt{\,\times\,}}\left({\frac{{\mathtt{11}}}{{\mathtt{4}}}}\right) = {\mathtt{22}}$$ in this case you would have $${\frac{{\mathtt{352}}}{{\mathtt{16}}}} = {\mathtt{22}}$$. I would recommend the first operation for siplicity. But you should understand common denominators and multiplication of denominators, also. Also, always show your work in case you make a mistake your teacher can show you your error(s)