Greatest Common Factor GCF

1

• Greatest Common Factor (GCF)
• Least Common Multiple (LCM)
• Reducing Fractions to Simplest Form

2

• 12 40

• Find a number that will divide both numbers
  evenly.
• 2 will work. Draw an upside down Division bar
  and place the 2 outside.
• 3 and 10 only have 1 in common so stop here.

2
2
6 20
3 10
3

• The numbers outside the yellow lines are used to
  find the gcf and lcm.
• By enclosing these numbers in you create an L.
• The GCF is found by multiplying the numbers in
  the top part of the L.
• The LCM is found by multiplying all the numbers
  in the L.

• 12 40

2
2
6 20
3 10
GCF 2 x 2 4
LCM 2 x 2 x 3 x 10 120
4

• Reducing Fractions to Simplest Form

• Take the fraction 12/40
• The numerator is 12 and the denominator is 40.
• The reduced fraction is 3/10

N
D

• 12 40

2
2
6 20
3 10