I am not finding it in my book. It has been awhile for me to do this. Most of the problems deal with this?

A "holding period" return, without any further qualifications, is the easiest type of return to calculate because you don't worry about re-stating it to conform with any particular time. It's simply the return derived from looking at the beginning and ending values, without regard for the length of the holding interval.

If an asset started with a value of 100 and ended at a value of 125, it experienced a 25% gain, or return. Without any further information about how much time elapsed between those two values, you can simply say it had a 25% "holding period" return---whether that holding period was a week, a quarter, or 7 years.

Most holding-period returns, though, are eventually re-expressed to some common yardstick (usually an 'annualized' return) to facilitate comparisons across multiple assets having arbitrary holding periods.