Sum Song

If the price of a cat
Is times two of a rat
And the answer subtracted from ten,
Of the price of a vole
That's been pushed down a hole
And divided by fifty and then,
Added onto the cost
Of a rabbit that's lost
Any number of feet multiplied,
By how much you would spend
In deciding to lend
To a herring whose hands have been tied.
Now the answer, of course,
Is the price of a horse
Take away seven-eights of a pound
Of the money that's spend
Finding out where it's went,
Not that it's ever there to be found.