Things That Cut
This is a canary knife. It is used to cut cardboard. The cardboard is supported by two thick pieces of wood. Each piece of wood is 50cm long.

This kind of strong construction wood is called a 2x4 [or "two-by-four"].  There is a 1cm gap between the two pieces.The two pieces are clamped firmly in a vise. This makes cutting easier and
safer!
Cutting Smaller pieces of Cardboard
Cutting Larger Pieces of Cardboard
Fine Tooth Cross Cut Saw
A small fine tooth cross cut hand saw is the easiest way of cutting a larger piece of cardboard. The cardboard is resting on a cutting bench.

This cutting bench is also called a jig. A jig is a  device that supports or holds a piece of work and guides the tools operating on it.

The most popular cardboard cutting tool I had in my classroom was a scroll saw. If you use a scroll saw don't forget your
safety glasses!
Cutting Bench
Scroll Saw + Safety Goggles
Key Hole Saw
Utility Knife Safety Video