Given that you are saving up to buy a bicycle.
It costs $85.99
And you already have $47.52.
The amount you need to add to purchase the bicycle will be;
[tex]\begin{gathered} A=\text{ \$85.99 - \$47.52} \\ A=\text{ \$38.47} \end{gathered}[/tex]Therefore, you need $38.47 more