A Cardinal Number says how many of something, such as one, two, three, four, five, etc.
It does not have fractions or decimals, it is only used for counting.
How to remember: "Cardinal is Counting"
An Ordinal Number tells us the position of something in a list.
1st, 2nd, 3rd, 4th, 5th and so on (see Cardinal and Ordinal Numbers Chart for more.)
How to remember: "Ordinal says what Order things are in".