Why are imaginary numbers… imaginary?

Imaginary numbers are like invisible steps that help us solve puzzles we can't see clearly at first.

Imagine you're playing with blocks and you want to know how many blocks you need to go from one shelf to another. If the shelves are 3 blocks apart, you just count them. But what if you had a mystery block that made things further away? That’s like having negative numbers, they help when things go backwards or down.

Now, imagine you're trying to find the square root of something, like finding a number that when multiplied by itself gives you 9, that’s easy: it's 3. But what if you want a number that when multiplied by itself gives you -1? That doesn’t happen with regular numbers, but we can invent one! We call it i, the imaginary unit.

Think of it like having a special toy that only works in secret, it doesn’t appear on your count, but it helps make other toys work better. You can’t touch i with your hands, but you can use it to solve bigger problems, just like how you use blocks to build towers.

So even though imaginary numbers are called imaginary, they're not made up, they’re just tools we invented to help us do more interesting math!

Take the quiz →

Examples

  1. A kid uses a number line to count apples, but then needs something for square roots of negative numbers.
  2. Imaginary numbers help solve equations that don’t have real solutions.
  3. Teachers sometimes call them 'imaginary' because they aren't like the numbers you use every day.

Ask a question

See also

Discussion

Recent activity