Write the following binary number

$1111$

in expanded form. Use $x$ for multiplication when needed and ${?}^{{?}^{{?}^{?}}}$ for power. For example,

$12^3$ can be written as $12^{{?}^{{?}^{?}}}3.$ It is also possible to avoid using ${?}^{{?}^{{?}^{?}}}.$ You would have to use $x^2$ button on a tool bar. You are more than welcome to learn how to do it$.$ Either way is fine.