A unit fraction is one of the form $$\frac{1}{a}$$ where a is a natural number ($$\neq $$1). Any proper fraction can be written as the sum of two or more unit fractions.
{Ex.$$\frac{1}{2}=\frac{1}{3}+\frac{1}{6}, \frac{5}{6}=\frac{1}{2}+ \frac{1}{3}, \frac{1}{24}= \frac{1}{54}+ \frac{1}{72}+ \frac{1}{108}$$}.
In the case of $$\frac{1}{2}$$,the factors of 2 are 1 and 2 only
$$\frac{1}{2}= \frac{1+2}{2(1+2)} =\frac{1}{2(1+2)} + \frac{2}{2(1+2)} = \frac{1}{6} + \frac{1}{3}$$
Express $$\frac{1}{15}$$ as the sum of two different unit fractions in 4 different ways.