2. Write the number as an improper fraction.
- 641.8989 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:
641.8989 = 641.8989/1
Turn the top number into a whole number.
- Multiply both the top and the bottom by the same number.
- This number is: 10,000.
- 1 followed by as many 0-s as the number of digits after the decimal point.
641.8989/1 =
(641.8989 × 10,000)/(1 × 10,000) =
6,418,989/10,000
3. Reduce (simplify) the fraction above:
6,418,989/10,000
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).
6,418,989 = 32 × 53 × 13,457
10,000 = 24 × 54
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 (32 × 53 × 13,457; 24 × 54) = 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.
6,418,989 ÷ 10,000 = 641, remainder = 8,989 ⇒
6,418,989 = 641 × 10,000 + 8,989 ⇒
6,418,989/10,000 =
(641 × 10,000 + 8,989) / 10,000 =
(641 × 10,000) / 10,000 + 8,989/10,000 =
641 + 8,989/10,000 =
641 8,989/10,000