2. Write the number as an improper fraction.
- 72.85 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:
72.85 = 72.85/1
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.
72.85/1 =
(72.85 × 100)/(1 × 100) =
7,285/100
3. Reduce (simplify) the fraction above:
7,285/100
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).
7,285 = 5 × 31 × 47
100 = 22 × 52
Calculate the greatest (highest) common factor (divisor), GCF.
Multiply all the common prime factors by the lowest exponents.
GCF (5 × 31 × 47; 22 × 52) = 5
Divide both the numerator and the denominator by their GCF.
7,285/100 =
(5 × 31 × 47)/(22 × 52) =
((5 × 31 × 47) ÷ 5) / ((22 × 52) ÷ 5) =
(31 × 47)/(22 × 5) =
1,457/20
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.
1,457 ÷ 20 = 72, remainder = 17 ⇒
1,457 = 72 × 20 + 17 ⇒
1,457/20 =
(72 × 20 + 17) / 20 =
(72 × 20) / 20 + 17/20 =
72 + 17/20 =
72 17/20