What is 3.9857857857... as a Fraction?

3.9857 equals 199094995 as a fraction.

How do you turn 3.9857 repeating into a fraction?

Detailed Answer:

Step 1: To convert 3.9857 repeating into a fraction, begin writing this simple equation:

n = 3.9857 (equation 1)

Step 2: Notice that there are 3 digits in the repeating block (857) and 1 digit in the non-repeating part (9). Multiply both sides by 10⁴ = 10000.

10000 × n = 39857.857 (equation 2)

Step 3: Now subtract equation 1 from equation 2 to cancel the repeating block (or repetend) out.

10000 × n = 39857.857
   10 × n = 3.9857
 9990 × n = 39818

398189990 could be the answer, but it still can be put in the simplest form, i.e., reduced.

To simplify this fraction, divide the numerator and denominator by 2 (the GCF - greatest common factor).

n = 398189990 = 39818 ÷ 29990 ÷ 2 = 199094995. So,

3.9857 = 199094995 as the lowest possible fraction.

As the numerator is greater than the denominator, we have an improper fraction, so we can also express it as a mixed number, thus 199094995 is also equal to 349244995 when expressed as a mixed number.

The repeating decimal 3.9857 (vinculum notation) has a repeated block length of 3. It is also represented as 3.9857857857... (ellipsis notation) which equals approximately 3.9857857857857857 (decimal approximation)(*).

The recurring decimal 3.9857 can be written as a ratio of two integers having 19909 as the numerator and 4995 as the denominator. So, it is a rational number (named after ratio). It can be shown that a number is rational if its decimal representation is repeating or terminating.

(*) At present, there is no single universally accepted notation or phrasing for repeating decimals.