Arithmetic Grade Five

Lesson Forty-four: Multiplying By Tens


Study the following number sentences.

  100 x 100 = 10000		2000 x 20 = 20000

  1000 x 1000 = 1000000		300 x 4000 = 1200000

As you can see, when we multiply numbers like these we can wind up with a lot of zeroes. Normally we would put commas in them like this:

	10,000			20,000

	1,000,000		1,200,000

The activities will not work with commas, though, and so you will have to be extra careful when entering zeroes. The nice thing about the commas is that it makes it easy to see the place value columns.

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