Greatest / Highest Common Factor / Multiple / Divisor

When do you need the GCF of two or more numbers?

1. Factoring

   ex. 24a + 40

   8 × 3 + 8 × 5

   8(3a + 5)

2. Add or Subtract and Reduce Fractions

   ex. 5/24 + 6/40 -->

   Get a COMMON DENOMINATOR: (5 × 40)/(24 × 40) + (6 × 24)/(40 × 24)

   200/960 + 144/960 = (200+144)/960

   344/960 --> simplify/reduce

   divide both by GCF 8: 344 ÷ 8 = 43

   960 ÷ 8 = 120

   43/120