Using BYOD - Number Theory Worksheet 1- Factors, LCM, HCF, Prime factors
To find all possible factors of 12:
Google Mathway, click on Algebra, type in 12 and click on ‘all possible factors’.
Answer given will be -12,-6,-4,-3,-2,-1,1,2,3,4,6,12 which includes the negative
integers as well.
Now find all possible factors of 30: ___________________________________
To find Lowest Common Multiple (LCM)
Get on Mathway, click on Algebra and type in 12,15 and click on ‘find the LCM’.
The answer given is 60. Similarly type in 32×5, 52×33 (use Mathway to type in
powers,and the star on Mathway keyboard for the multiplication sign. Note
that multiplication comes up as a dot) and find the LCM. The answer given is
675 and when you factorise it is 33×52.
Find the LCM of 30 and 48: __________________________________________
Find the LCM of 23×32 and 2×33:______________________________________
To find the Highest Common Factor (HCF) of 12,15
Google Mathway, click on Algebra, type in 12,15 and click on ‘find the HCF’.
The answer is given which is 3.
Find the HCF of 30 and 48: __________________________________________
To write 12 as a product of its prime factors.
Google Mathway, click on Pre-Algebra or Algebra, type in 12 and ‘find the
prime factorisation’. The answer given is 1×2×2×3 which is 22×3. Remember
that the dot is a multiplication sign in Mathway.
Write the following numbers as a product of prime factors:
48
=
685
=
2347 =
121 345 678 =
Use prime factorisation to find the LCM and HCF of i)12 and 15 ii) 56 and 80 .
Nataraj 2014, Selwyn College
Nataraj 2014, Selwyn College