Higher November 2021 Unit 1 Q2
2.
(a) Find the Lowest Common Multiple (LCM) of 60 and 72. [2]
LCM of 60 and 72 is ……………………
(b) Express 882 as a product of its prime factors.
Give your answer in index form. [3]
Give your answer in index form. [3]
| Scheme | Marks | Comments |
|---|---|---|
| 360 | B2 | Mark final answer. B1 for \(2^3 \times 3^2 \times 5\) OR B1 for any other common multiple e.g. 720, 1080 etc. unambiguously identified as a final answer OR B1 for sight of correct prime factors e.g. \(60 = 2^2 \times 3 \times 5\) or equivalent AND \(72 = 2^3 \times 3^2\) or equivalent OR Accurate Venn diagram showing correct prime factors OR B1 for sight of 60, 120, 180, 240, 300, 360, …. AND 72, 144, 216, 288, 360 with no further numbers. |
| Scheme | Marks | Comments |
|---|---|---|
| For a single method that produces 2 prime factors from the set {2, 3, 3, 7, 7} before the 2nd error. | M1 | Must be a method of ‘repeated division’. |
| 2, 3, 3, 7, 7 | A1 | C.A.O. for sight of the five correct factors. (Ignore 1s) |
| \(2 \times 3^2 \times 7^2\) | B1 | F.T. ‘their primes’ provided at least one index form used with at least a square. Do not F.T. non-primes. Allow \((2)(3^2)(7^2)\) and \(2.3^2.7^2\) Do not allow \(2{,}3^2{,}7^2\). Inclusion of 1 as a factor gets B0. |