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##### multiplying two 2-digit numbers

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 Kat's Mom Joined: Jun 2006 Posts: 1,538 Senior Member
Kat's Mom

Joined: Jun 2006
Posts: 1,538
Senior Member
multiplying two 2-digit numbers
10-09-2017, 12:57 PM
 #1

I am a first-grade teacher with a daughter in fourth grade. Due to her math benchmark scores, it was decided to bump her up to math class with the fifth graders. They are reviewing multiplying two 2-digit numbers, and because my daughter was never instructed in this, she is struggling a bit. I have shown her the traditional column method. I have also shown her how to multiply the ones and the tens separately and add them together (ie 46 x 24 is the same as 46 x 20 + 46 x 4). I also showed her a Khan Academy video. Do any of you have other visual tricks or video that might help her to catch on quickly? Thanks!

 1956BD Joined: Aug 2007 Posts: 23,595 Senior Member
1956BD

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Check You Tube
10-09-2017, 02:13 PM
 #2

You will need to preview but hopefully you will find more help.

 owl98 Joined: Aug 2008 Posts: 1,311 Senior Member
owl98

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10-09-2017, 02:30 PM
 #3

This goes along with multiplying the tens and ones separately, a little more broken down, and with a visual.

Have you shown her the open array method?
In the example you have above, you would draw a rectangle and label the top 46 and the side 24. You would break the 46 apart by saying 40 + 6. I draw a line through the rectangle at the plus sign. I break apart the 24 by saying 20 + 4. And draw a line through the array at the plus sign. There should now be four pieces to your array. I then multiply all of the parts of the array (40 x 20) + (6 x 20) + (40 x 4) + (4 x 6). When you add them, you will get the correct answer.
Here is a video from you tube so you can see what I mean a little better.

Hope this helps!

 roo Joined: Sep 2005 Posts: 6,341 Senior Member
roo

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10-10-2017, 05:44 PM
 #4

 missteaching Joined: Sep 2008 Posts: 24 New Member
missteaching

Joined: Sep 2008
Posts: 24
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11-16-2017, 02:52 PM
 #5

What method do they use when instructing the other fourth graders? I would find the way that you / her teacher think works for her and stick with that way so that she doesn't get confused ... good luck!

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