Question

Write as fraction into lowest form $0.80$ ?

Answer 1

Step 1:Remove the decimal point

As there are two digits after decimal. So multiply and divide the decimal by $100$ to remove the decimal.

$\begin{array}{rcl}0.80& =& 0.80\times \frac{100}{100}\\ & =& \frac{0.80\times 100}{100}\\ & =& \frac{80}{100}\end{array}$

Step 2: Find the greatest common factor of $80$ and $100$

Prime factorisation of $80$ and $100$ are $\left(2\times 2\times 2\times 2\times 5\right)$ and ($(2\times 2\times 5\times 5)$ respectively.

Hence, the GCF of $80$ and $100$ is $2\times 2\times 5=20$

Step 3: Divide both numerator and denominator by their GCF

$\frac{80}{100}=\frac{80÷20}{100÷20}=\frac{4}{5}$

Hence, $0.80$ in fraction in its lowest form is $\frac{4}{5}$