What is 21.63888... as a Fraction?

21.638 equals 77936 as a fraction.

How do you turn 21.638 repeating into a fraction?

Detailed Answer:

Step 1: To convert 21.638 repeating into a fraction, begin writing this simple equation:

n = 21.638 (equation 1)

Step 2: Notice that there is 1 digit in the repeating block (8) and 2 digits in the non-repeating part (63). Multiply both sides by 10³ = 1000.

1000 × n = 21638.8 (equation 2)

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

1000 × n = 21638.8
 100 × n = 21.638
 900 × n = 19475

19475900 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 25 (the GCF - greatest common factor).

n = 19475900 = 19475 ÷ 25900 ÷ 25 = 77936. So,

21.638 = 77936 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 77936 is also equal to 212336 when expressed as a mixed number.

The repeating decimal 21.638 (vinculum notation) has a repeated block length of 1. It is also represented as 21.63888... (ellipsis notation) which equals approximately 21.6388888 (decimal approximation)(*).

The recurring decimal 21.638 can be written as a ratio of two integers having 779 as the numerator and 36 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.