Question

You have \(\dfrac{4}{5}\) of a chocolate bar. You give \(\dfrac{3}{10}\) of the bar to your friend. How much chocolate do you have left?

Answer 1

The amount of chocolate bar you have \(= \dfrac{4}{5}\)
The amount of chocolate you gave to your friend \(=\dfrac{3}{10}\)
The amount of chocolate you have left \(= \dfrac{4}{5} - \dfrac{3}{10}\)
To subtract unlike fractions, first convert them into like fractions by finding the equivalent fractions with the same denominator.
\(\dfrac{4}{5} = \dfrac{4 \times 2}{5 \times 2} =\dfrac{ 8}{10}\)
\(\dfrac{4}{5} -\dfrac{ 3}{10} = \dfrac{8}{10} - \dfrac{3}{10} = \dfrac{8 - 3}{10} = \dfrac{5}{10}\)
\(\dfrac{5}{10} = \dfrac{5 \div 5}{10 \div 5} = \dfrac{1}{2}\)
\(\dfrac{5}{10}\) is also equivalent to \(\dfrac{1}{2}\).
Hence, options C and D are correct.