SASMO 2021 Grade 5 Question 9

Jill puts the digits 2, 3, 4, 5 and 6 exactly once into the five boxes in the expression shown, to obtain the largest possible fraction. In simplest form its numerator is $n$ and denominator is $d$. Find $n+d$.

The layout means $a+\dfrac{b}{c+\dfrac{d_1}{e}}$, with one digit in each box.