Guided Example #3 - Natural Numbers

Open-ended Guided Example

(SMR 3.1a) Prove: The least common multiple of two integers is equal to the product of the integers divided by the greatest common factor of the two integers.

Try this proof by yourself.

 

Step 1

Step 2

Let G represents the GCF of a and b.

Step 3

Then a=Gx and b=Gy , where x and y are relatively prime.

Step 4

The LCM of a and b is Gxy .

Step 5

Since x=aGandy=bG , by substitution, Gxy=G(aG)(bG) .

Step 6

Hence, Gxy (or the LCM of a and b) = abG .

All Steps

Let G represents the GCF of a and b.

Then a=Gx and b=Gy , where x and y are relatively prime.

The LCM of a and b is Gxy .

Since x=aGandy=bG , by substitution, Gxy=G(aG)(bG) .

Hence, Gxy (or the LCM of a and b) = abG .