I’ve had this question quite a lot recently so I thought I’d clear that up. My other post from today tells you what an algorithm is if you want to read that.
An algorithm is a set on instructions that have an initial and terminating state – a basic but correct definition.
An equation is a mathematical statement with an equals sign – 2 expressions are equal. That’s why it’s called an equation.
Algorithms, like PageRank that many of you are familiar with, at some level of complexity, is an algorithm. It contains other algorithms too. These algorithms contain equations and other kinds of mathematical expressions (it contains any number of mathematical symbols). These provide numbers for the system to work with.
There are not just equations at work here, there is also use of arithmetic, algebra and rational expressions for example.
Even when we want to do something with human language, we have to put the sentences, words, all of that stuff into a numeric format. To do this we use any number of algorithms. We then need to do something with these numbers to get a result, so we plug these numbers into algorithms that are designed to work with those and give us a reasonable and useful output.