A computer is something that takes an input (like some button press), processes that input, and then gives you an output (like Mario jumping on a Goomba).

The processing is a mathematical problem that the computer has to solve. It does it by breaking the problem down into a whole bunch of very small problems: like the Lego of mathematics.

Some problems are easier to build out of these basic building blocks than others, and so there is a difference in how fast the computer can solve them.

Quantum computers use different building blocks to normal computers. They are like Lego Technic instead of Duplo. So they'll be able to solve problems that normal computers will struggle with. 😉