4MA0 Higher January 2017 Paper 3 Q3
3 Show that \(\;5\dfrac{2}{3} - 3\dfrac{4}{5} = 1\dfrac{13}{15}\)
(3)
| Scheme | Marks |
|---|---|
| \(\dfrac{17}{3} - \dfrac{19}{5}\) | M1 |
E.g. \(\dfrac{85}{15} - \dfrac{57}{15}\) or \(\dfrac{17 \times 5 - 3 \times 19}{15}\) oe | M1 |
| shown | A1 |
| (3) | |
| (3 marks) |
Notes
M1: for correct improper fractions (subtraction sign not necessary)
OR two improper fractions with a common denominator with at least one of the fractions correct
A1: dep on M2 for correct conclusion to \(1\dfrac{13}{15}\) from correct working with sight of the result of the subtraction e.g. \(\dfrac{28}{15}\)
Alternative method
| Scheme | Marks |
|---|---|
| \((5)\dfrac{10}{15} - (3)\dfrac{12}{15}\) | M1 |
| \(-\dfrac{2}{15}\) | M1 |
| shown | A1 |
Notes
M1: for two correct fractions with a common denominator a multiple of 15
A1: dep on M2 for correct conclusion to \(1\dfrac{13}{15}\) from correct working with sight of the result of the subtraction e.g. \(\dfrac{28}{15}\) or \(2 - \dfrac{2}{15}\)
Alternative method
| Scheme | Marks |
|---|---|
| E.g. \(5\dfrac{10}{15} - 3\dfrac{12}{15}\) | M1 |
| E.g. \(4\dfrac{25}{15} - 3\dfrac{12}{15}\) | M1 |
| shown | A1 |
Notes
M1: for two correct fractions with a common denominator a multiple of 15
M1: for a complete correct method
A1: dep on M2 for correct conclusion to \(1\dfrac{13}{15}\) from correct working