What is an algorithm? How computers know what to do with data

Computation is the heart of an algorithm and involves arithmetic, decision-making, and repetition.

To apply this to getting dressed, you make decisions by doing some math on input quantities. Wearing a jacket might depend on the temperature. To a computer, part of getting dressed algorithm would be "if it is below 50 degrees and raining, then pick the rain jacket and a long-sleeved shirt."

The last step of an algorithm is output - expressing the answer.

Output to a computer is usually more data. It allows computers to string algorithms together in complex ways to produce more algorithms. Output can also present information, such as putting words on a screen.

It can sometimes be too complicated to spell out a decision-making process. Machine learning tries to "learn" based on a set of past decision-making examples.

Machine learning is used for things like recommendations, predictions, and looking up information.