Lowest common multiple | Maths | Quizalize & Oak National Academy

Starter quiz

Complete the statement. A number that is a multiple of two or more numbers is called a ______ multiple.

'common' ✓
Match each number with its first four multiples.

First four multiples of 2:

⇔

2, 4, 6, 8 ✓

First four multiples of 4:

⇔

4, 8, 12, 16 ✓

First four multiples of 3:

⇔

3, 6, 9, 12 ✓

First four multiples of 12:

⇔

12, 24, 36, 48 ✓
Which of the following is a factor of $2^3\times3^4\times5^2$ and of $2^3\times3^5\times5$ ?

$2^3\times3^5\times5^2$

$2^2\times3^4\times5$ ✓

$2^2\times3^4\times5$ ✓

$2^3\times3^4\times5^2$
Select the correct statements.

240 as a product of prime factors is $2^4 \times 3 \times 5$ ✓

240 as a product of prime factors is $2^2 \times 3^2 \times 5$

180 as a product of prime factors is $2^2 \times 3 \times 5$

180 as a product of prime factors is $2^2 \times 3^2 \times 5$ ✓
The HCF of 84, 180 and 120 is ______.

'12' ✓
The HCF of 126, 945 and 189 is 63. The missing prime factor in the Venn diagram is ______.

'7' ✓

What does the L stand for in LCM?

'lowest' ✓
Which of the following is not a multiple of $2\times3^2\times5$ ?

$2^2\times3^2\times5$

$2^2\times3^3\times5$

$2^2\times3\times5$ ✓

$2^2\times3^2\times5^3$
Given that $12 = 2^2\times3$ , write 60 as a product of its prime factors.

$2^3\times3$

$2^2\times3\times12$

$2^2\times3^2\times5$

$2^2\times3\times5$ ✓
The LCM of 18 and 30 is ______

'90' ✓
The LCM of 70 and 42 is 210. So, the missing prime factor in the Venn diagram is ______

'7' ✓
The LCM of 12, 20 and 84 is ______

'420' ✓

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Common multiples can be found using the prime factorisation of numbers
The lowest common multiple of two numbers can be found by comparing the prime factorisation of both numbers
Sometimes a Venn diagram can help identify the lowest common multiple of two numbers
The lowest common multiple of more than two numbers can be found using prime factorisation

When using a Venn diagram misplacement of factors is common.

Encourage students to check that the product of factors in each set is the correct integer.

Lowest common multiple - The lowest common multiple is the lowest number that is a multiple of two or more integers.
Lcm - LCM is an abbreviation for lowest common multiple.