4MA0 Foundation June 2011 Paper 1 Q18
18 Show that \(\dfrac{5}{6} - \dfrac{3}{4} = \dfrac{1}{12}\)
(2)
| Scheme | Marks |
|---|---|
\(\dfrac{10}{12}\) and \(\dfrac{9}{12}\) eg \(\dfrac{10 - 9}{12}\), \(\dfrac{10}{12} - \dfrac{9}{12}\) | B2 |
| (2) | |
| (Total 2 marks) |
Notes
B2: B1 for \(\dfrac{10}{12}\) or \(\dfrac{9}{12}\)
or for \(\dfrac{5 \times 2}{6 \times 2}\) or \(\dfrac{3 \times 3}{4 \times 3}\)
Alternative method
B1 for both fractions correctly expressed as equivalent fractions with denominators that are common multiples of 6 and 4 eg \(\dfrac{20}{24}\) and \(\dfrac{18}{24}\)
or \(\dfrac{5 \times 4}{6 \times 4}\) or \(\dfrac{3 \times 6}{4 \times 6}\)
B1 for correct answer which is equivalent to \(\dfrac{1}{12}\) eg \(\dfrac{2}{24}\)
SC B1 for multiplying both sides by 12 ie 10 − 9 = 1