the factors of

1) 36 are

(1×36),(2×18),(3×12),(4×9),(6×6)

40 are

(1×40),(2×20),(4×10),(5×8)

then look for numbers they have in

common

1,2,4,…

and pick the largest value from the

list and that is the GCF (4)

the lowest common multiple (LCM) is the smallest common multiple between 2 or more numbers

1) we found the common factors for

were 1,2,4 (but we actually ignore 1

because it is the multiplicative identity)

and choose the smallest number (2)

use these same steps for number 2

and you’ll be done

factors of 40 – 2 x 2 x 2 x 5

GCF – 4

LCM – 4 x 9 x 5 x 2 = 360

factors of 21 – 3 x 7, of 106 – 2 x 53, 63 – 3 x 3 x 7

GCF – 1 ????? are you sure that the middle number isn’t 105 ??

LCM – 106 x 63 = 63378