Sequences and Series
Numbers often progressively change. A tree may be grow in height every year. A population of flies may increase every day. Interest may be added to a bank account every year. As mathematicians we often simplify the situation and assume that it is either an "Arithmetic" or a "Geometric" series.
“An infinite number of mathematicians walk into a bar. The first mathematician says to the bartender: 'I'll have a glass of orange juice.' The second says: 'I'll have half of a glass of orange juice.' The third says: 'I'll take a quarter of a glass of orange juice.' "The bartender pulls out two glasses and starts filling them with orange juice. One of the mathematicians looks and asks: 'Why are you only using two glasses?' The bartender says: 'If you are really mathematicians you should know your limits!'”
Here is a link back to the UPmaths homepage.