Making Sense of Numbers
Four ideas that sit underneath every sum you will ever do: which family a number belongs to, why a digit changes value when it moves, which operation happens first, and how numbers divide into and multiply out of each other. Nothing here needs a calculator, and each part assumes the one before it.
CodePLU Goal
Upgrading Human Mental Models
Learn how to think in Workflows
What Are the Different Types of Numbers?
Counting numbers, integers, rationals and irrationals explained in plain words — then sort each number into its family yourself in an interactive playground.
Why Does a Digit's Position Change Its Value?
The same digit can be worth 5 or 500 depending on where it sits. Learn how columns decide a digit value, then build 535 down into its columns in an interactive playground.
Why Does the Order of Operations Matter?
Two people can get two different answers from the same sum unless they agree on an order. Learn the rule and build the steps yourself in an interactive playground.
What's the Difference Between a Factor and a Multiple?
Factors go into a number; multiples come out of it. Learn which direction each word points, then sort three numbers by how they relate to 12.