How can we find the median of grouped data?

How can we find the median of grouped data?
You put the numbers in order from least to greatest then, start at the beginning and end, and cross out one... two... three... four..., then so on, until you have only one number in the middle.
Example 27,44,45,46,52; cross out 27, then... 52, then... 44, then... 46, then... 45 is the last answer left, so 45, is your answer.

man, whoever answered this question is a total fool. they wanted to know how to find the median of GROUPED DATA not just the median.
wow what a fool.