What is 2.158571857185718571... as a Fraction?

2.158571 equals 17986383325 as a fraction.

How do you turn 2.158571 repeating into a fraction?

Detailed Answer:

Step 1: To convert 2.158571 repeating into a fraction, begin writing this simple equation:

n = 2.158571 (equation 1)

Step 2: Notice that there are 4 digits in the repeating block (8571) and 2 digits in the non-repeating part (15). Multiply both sides by 10⁶ = 1000000.

1000000 × n = 2158571.8571 (equation 2)

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

1000000 × n = 2158571.8571
    100 × n = 2.158571
 999900 × n = 2158356

2158356999900 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 12 (the GCF - greatest common factor).

n = 2158356999900 = 2158356 ÷ 12999900 ÷ 12 = 17986383325. So,

2.158571 = 17986383325 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 17986383325 is also equal to 21321383325 when expressed as a mixed number.

The repeating decimal 2.158571 (vinculum notation) has a repeated block length of 4. It is also represented as 2.15857185718571... (ellipsis notation) which equals approximately 2.1585718571857185718571 (decimal approximation)(*).

The recurring decimal 2.158571 can be written as a ratio of two integers having 179863 as the numerator and 83325 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.