One of the types of simple machines is the Lever
The principle of leverage can be derived using Newton's laws of motion, and modern statics. The lever is depending on the weight. Just like the toaster. You just pull down the toaster and the toaster goes down and automatically heat it.
Compound Machines (Axe)
Compound Machines are types of machines that have more than 1 simple machines in them. For example there is the Axe. It is both a wedge and a lever. It is a lever because you can swing around and the wedge is for cutting the wood. A compound machines needs more than one. The compound machine can't work without each other. If it was only the lever it can't cut things. If it is just a wedge you can't swing or move it. It cannot work without each other.