A magnet contains two poles: a south pole and a north pole.

Different poles attract each other strongly.

If a magnet is cut in two, the result is two smaller magnets, both of which have their own south and north poles. 

Various metals, such as iron, nickel and kobolt, are magnetic. They form a strong magnetic force when a magnet is brought near them. 

The similar poles of two magnets repel one another strongly. This is why strong magnets are hard to place next to one another.