2. Write the number as an improper fraction.
- 13.09 can be written as an improper fraction.
- An improper fraction = the numerator is larger than or equal to the denominator..
Write down the number divided by 1, as a fraction:
13.09 = 13.09/1
Turn the top number into a whole number.
- Multiply both the top and the bottom by the same number.
- This number is: 100.
- 1 followed by as many 0-s as the number of digits after the decimal point.
13.09/1 =
(13.09 × 100)/(1 × 100) =
1,309/100
3. Reduce (simplify) the fraction above:
1,309/100
to the lowest terms, to its simplest equivalent form, irreducible.
To reduce a fraction to the lowest terms divide the numerator and denominator by their greatest (highest) common factor (divisor), GCF.
Factor the numerator and denominator (prime factorization).
1,309 = 7 × 11 × 17
100 = 22 × 52
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
But, the numerator and the denominator have no common factors.
GCF (7 × 11 × 17; 22 × 52) = 1
The numerator and the denominator are coprime numbers (no common prime factors, GCF = 1). So, the fraction cannot be reduced (simplified): irreducible fraction.
4. The fraction is an improper one, rewrite it as a mixed number (mixed fraction):
- A mixed number = an integer number and a proper fraction, of the same sign.
- Example 1: 2 1/5; Example 2: - 1 3/7.
- A proper fraction = the numerator is smaller than the denominator.
1,309 ÷ 100 = 13, remainder = 9 ⇒
1,309 = 13 × 100 + 9 ⇒
1,309/100 =
(13 × 100 + 9) / 100 =
(13 × 100) / 100 + 9/100 =
13 + 9/100 =
13 9/100