Answer
$102_{four}$
Work Step by Step
Rightmost column:
$3+3=6_{ten}=1\times 4+2\times 1=12_{four}$
record the 2, carry the 1:
$.\qquad \ \ $1
$.\qquad \ \ 23_{four}$
.$\quad \ +\ 13_{four}$
$.\quad \ \ \ \_\_\_\_$
$.\qquad \ \ \ \ 2_{four}$
Next column:
$1+2+1=4=1\times4+0\times1=10_{four}$
record the 10:
$.\qquad \ \ $1
$.\qquad \ \ 23_{four}$
.$\quad +\ \ \ \ 13_{four}$
$.\quad \_\_\_\_$
$.\qquad \ 102_{four}$
result: $102_{four}$
