LCM and HCF

HCF of 64 and 132:  2|64  132
                                 2 |32  66
                                    |16  33

2x2 is 4. Therefore highest common factor is 4. To get the lowest common multiple from here we do 2x2x16x33. The lowest common factor is 2112.


HCF of 328 and 428:  4|328  428
                                     |82  107

4x1 is 4. Therefore the highest common factor is 4. To get the lowest common multiple from here we do 4x1x82x107. The lowest common multiple is 35096.

The divisors multiplied with each other give the HCF.
The divisors multiplied with each other and the quotients gives the LCM

Easy once you practise.