To find the GCF, one method is to look at your numbers and find a factor that they both can divide by.

522 | 216 | 864 |

For the numbers here, I can see that they are both divisible by 9. I write the 9 in the next section below and divide both the numbers and write the quotients beneath the original.

522 | 216 | 864 | |

9 | 58 | 24 | 96 |

Repeat the process with the next sets of numbers.

522 | 216 | 864 | |

9 | 58 | 24 | 96 |

2 | 29 | 12 | 48 |

Once your last set of numbers don’t have a common factor, you multiply all the numbers in the left column together to find the GCF

522 | 216 | 864 | |

9 |
58 | 24 | 96 |

2 |
29 | 12 | 48 |

9 x 2= 18

The GCF of 522, 216 and 864 is 18

To find the LCM using this method, you multiply together all of the factors on the left column and the bottom row. (Creating an L shape for the LCM)

522 | 216 | 864 | |

9 |
58 | 24 | 96 |

2 |
29 |
12 |
48 |

9 x 2 x 29 x 12 x 48= 300 672

The LCM of 552, 216 and 864 is 300 672

I personally prefer the strategy given in class because it seems more logical to me. I find the numerical process easier to understand when it’s clear cut, rather than drawn out and being shown every single step.