Earlier you've learned how to calculate integers, now it's time
to learn how to calculate decimals.
When you are calculating with decimal numbers you are using the
same principles as when you are calculating with integers.
Decimal numbers are rational numbers and can be written as a
fraction of two numbers.
We name fractions like this:
Two fractions that are on the same denominator are called like
It is easy to add or subtract like fractions. If we add like
fractions we just add the numerators and this sum will be the new
numerator while the denominator is stays the same.
Factors that are not on the same denominator are called unlike
fractions. To find the sum or the difference of unlike fractions we
need to find a common denominator, the least common denominator -
To find the common denominator we multiply the first fraction by
the denominator of the second fraction.
You can rewrite fractions into decimal numbers by using long
Rewrite 2/4 as decimals.
This means that 2/4 is equal to 0.5. Decimals like 0.5 are
called terminating decimals.
Rewrite 2/3 as decimals.
3 is not a factor of 2. 3 is not a factor of 20 but a factor of
18 which gives us a remainder of 2.
When you multiply fractions, the numerators will be multiplied
with each other and the denominators will be multiplied with each
When you are dividing fractions, you are going to multiply the
first fraction by the multiplicative inverse of the second
Video lesson: Rewrite into decimals