A small discovery

I have found an easy way to remember the index number.

Laspeyres Index of Quantity:


Paasche Index of Quantity:


For the price index, we need a mirror image,

Laspeyres Price Index:


Paasche Price Index:


Hope that can help you to remember the index number, if you do not understand it at all, sorry all the above is not for you, surely the following joke too.

If we only know the prices and goods purchased yesterday, together with today prices, we can only show that we are worse off.