To determine the number of cups she still needs to chop we need to subtract the amount she already chopped to the amount she needs, then we have the equation:
[tex]x=3\frac{2}{3}-1\frac{1}{3}[/tex]This can be written as:
[tex]x+1\frac{1}{3}=3\frac{2}{3}[/tex]Now, we solve it:
[tex]\begin{gathered} x=3\frac{2}{3}-1\frac{1}{3} \\ x=\frac{11}{3}-\frac{4}{3} \\ x=\frac{7}{3} \end{gathered}[/tex]Therefore she needs to chop 7/3 more cups of onions.