39 divided by 3/4

$${\frac{{\mathtt{39}}}{\left({\frac{{\mathtt{3}}}{{\mathtt{4}}}}\right)}} = {\mathtt{52}}$$

If you didn't add the brackets the calculator would interpret it as:

$${\frac{{\frac{{\mathtt{39}}}{{\mathtt{3}}}}}{{\mathtt{4}}}} = {\frac{{\mathtt{13}}}{{\mathtt{4}}}} = {\mathtt{3.25}}$$

Best of luck!