Convert 0.8 to a rational number

0.8 is a repeating decimal

5 answers

The decimal 0.8 can be expressed as a rational number. It is not a repeating decimal; it is a terminating decimal.

To convert 0.8 to a rational number:

  1. Recognize that 0.8 can be written as \(\frac{8}{10}\).
  2. Simplify \(\frac{8}{10}\) by dividing the numerator and denominator by their greatest common divisor, which is 2.

\[ \frac{8 \div 2}{10 \div 2} = \frac{4}{5} \]

Therefore, the rational form of 0.8 is \(\frac{4}{5}\).

0.8 repeats

If the decimal is \(0.888...\), which is a repeating decimal, we can convert it to a rational number as follows:

Let \(x = 0.888...\).

  1. Multiply both sides by 10 to shift the decimal point: \[ 10x = 8.888... \]

  2. Now, you have two equations: \[ x = 0.888... \] \[ 10x = 8.888... \]

  3. Subtract the first equation from the second: \[ 10x - x = 8.888... - 0.888... \] \[ 9x = 8 \]

  4. Solve for \(x\): \[ x = \frac{8}{9} \]

Thus, if \(0.8\) is meant as a repeating decimal (\(0.888...\)), its rational form is \(\frac{8}{9}\). If you meant \(0.8\) as a non-repeating number, the rational form is \(\frac{4}{5}\). Please clarify if you meant \(0.888...\).

yes i did mean 0.888...

Great! Since you meant \(0.888...\) (which represents the repeating decimal), we already found that:

\[ x = 0.888... \]

  1. Multiply both sides by 10: \[ 10x = 8.888... \]

  2. Subtract the first equation from the second: \[ 10x - x = 8.888... - 0.888... \] \[ 9x = 8 \]

  3. Solve for \(x\): \[ x = \frac{8}{9} \]

Therefore, the rational representation of \(0.888...\) is \(\frac{8}{9}\).