Download Homework Factors and Multiples

Year 7 - Number 1 – Extension
Homework
Factors and Multiples
1.
For each of the following numbers write a list of their factors.
Then find the highest common factor for each set.
a)
12 and 18
2.
For each of the following numbers write down the first 8
multiples. For each pair what is the lowest common multiple?
a)
12 and 15
b)
b)
45 and 105
8 and 12
c)
c)
36, 84 and 132
10 and 15
Functional Question:
3.
There are two sets of traffic lights outside Eric’s house. One
day, he times how often they change. Light A turns green
exactly every 60 seconds. Light B turns green exactly every 80
seconds. At midday precisely, they both turn green together.
At what time will they both turn green together again?
Prime Numbers
4.
Write out the first 5 prime numbers
5.
Using just this list of numbers:
11, 18, 1, 4, 21, 24, 9, 3, 12, 2, 19
Write down all the prime numbers that you can see.
Year 7 - Number 1 – Extension
Extension Activity:
Factor Trees
Example: Find the prime factors of 280 using a factor tree and
express 280 as a product of its prime factors.
280
28
10
4
2
7
2
5
2
280 = 2 x 2 x 2 x 5 x 7
= 23 x 5 x 7
Using factor trees find the prime factors of the following numbers
and express as a product of prime factors.
a) 504
b) 210
c) 140
d) 864