Question

What is decimal notation?

Answer 1

Decimal notation is the representation of a fraction using the base $10$ and consisting of a decimal point.
Explanation:
Decimal notation is simply a form of a number using a decimal point. An example is $0.7$.
Decimals use the base ten. Thus, they have tenths, hundredths, thousandths, ten thousandths, etc. places. Check out the example below.
Now, it is useful to think about decimals in the context of fractions, because they are so often used together or even interchangeably. $0.7$ means seven tenths, as the $7$ is in the tenths place. It can be written as a fraction: $\frac{7}{10}$.
As the decimal expands into the hundredths, thousandths, etc. places, the denominator of the fraction similarly changes. For example, $0.70$ uses the hundredths place. Therefore, the fraction looks like this: $\frac{70}{100}$.
Fractions can be converted into decimals and vice versa. They are both equal, but written in different ways.