What is 2.12428428428... as a Fraction?

2.12428 equals 5305424975 as a fraction.

How do you turn 2.12428 repeating into a fraction?

Detailed Answer:

Step 1: To convert 2.12428 repeating into a fraction, begin writing this simple equation:

n = 2.12428 (equation 1)

Step 2: Notice that there are 3 digits in the repeating block (428) and 2 digits in the non-repeating part (12). Multiply both sides by 10⁵ = 100000.

100000 × n = 212428.428 (equation 2)

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

100000 × n = 212428.428
   100 × n = 2.12428
 99900 × n = 212216

21221699900 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 4 (the GCF - greatest common factor).

n = 21221699900 = 212216 ÷ 499900 ÷ 4 = 5305424975. So,

2.12428 = 5305424975 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 5305424975 is also equal to 2310424975 when expressed as a mixed number.

The repeating decimal 2.12428 (vinculum notation) has a repeated block length of 3. It is also represented as 2.12428428428... (ellipsis notation) which equals approximately 2.12428428428428428 (decimal approximation)(*).

The recurring decimal 2.12428 can be written as a ratio of two integers having 53054 as the numerator and 24975 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.