What are the properties of Rational Numbers?
They can be written as a result of a division between two whole numbers, however large.
Example: 1/7 is a rational number. It gives the ratio between 1 and 7. It could be price for one kiwi-fruit if you buy 7 for $1.
In decimal notation, rational numbers are often recognised because their decimals repeat. 1/3 comes back as 0.333333.... and 1/7 as 0.142857... ever repeating. Even 553/311 is a rational number (the repeating cylce is a bit longer)
There are also IRrational numbers that cannot be written as a division. Their decimals follow no regular pattern. Pi is the best-known example, but even the square root of 2 is irrational.