There is no way to express a mixed number as a proper fraction.
A fraction must be less than 1 to be proper.
If you have two and a half pizzas, that is more than one pizza.
It can be expressed as an improper fraction, though.
Two and a half pizzas is the same as five halves.
\(2\frac12=\frac52\)
My teachers taught it like this: multiply the whole number by the denominator and add the numerator to it..then take that number and put it over the denominator.
If you can't remember that, do it like this:
\(2\frac12=\frac21+\frac12=\frac{2\times2}{1\times2}+\frac12=\frac42+\frac12=\frac52\)
.
