4.2 as a Fraction

21/5

How to convert 4.2 to a fraction

4.2 as a fraction in simplest form is 21/5.

  1. Count the decimal places

    4.2 has 1 decimal place. The denominator is 10^1 = 10.

  2. Remove the decimal point

    Move the digits after the decimal into the numerator: 42/10.

  3. Find the greatest common divisor (GCD)

    GCD(42, 10) = 2.

  4. Divide by the GCD to simplify

    42 ÷ 2 = 21 and 10 ÷ 2 = 5, so the simplified fraction is 21/5.

  5. Express as a mixed number

    21 ÷ 5 = 4 with remainder 1, written as 4 1/5.