Multiplying with Multiples of 10

TGIF, Grade 5s!

Today in class we looked at patterns formed when multiplying multiples of 10.  We know a number is a multiple of 10 when it ends with a 0.

We started the lesson by finding the products for the following questions:
25 x 10 = ?
25 x 100 = ?
25 x 1000 = ?

Then we used the knowledge we got from the pattern to figure out what 25 x 100,000 would be.

We figured out that the pattern was to add as many zeroes as we see in the problem.  For example, 25 x 10 contains 1 zero, so the answer is 250.  25 x 100 has 2 zeroes, so the answer is 2 500.  25 x 1000 has 3 zeroes, so the answer is 25 000, etc.

We realised we could do the same thing with basic facts and place-value patterns:

7 x 8 = 56
7 x 80 = 560
7 x 800 = 5600
7 x 8000 = 56 000

I hope you have a great Thanksgiving weekend with your families.  Remember: Tuesday is Picture Day.  Better start planning those outfits now!  Maybe something like this?

See you Tuesday!

-Ms. Lewis.