How do you teach multiplication?

[Guest]

***Crossing my fingers that the formatting comes through and makes sense***

 

I learned and taught my son the traditional algorithm for multiplication:

 

       13

   x   13

        39

  +  130

      169

 

I'm looking through some Miquon pages I have and see they teach it a different way:

 

       13

  x    13

         9

       30

       30

  + 100

      169

 

I am wondering if there are any cons to teaching it this second way and if you do so, do you still teach the first way?

 

The second way is the way I've been trying to get him to think, 13x4? Mentally do 10x4 + 3x4. 52. I've been telling him to do that, but then having him do the traditional algorithm for longer problems. The Miquon worksheet I have (F-51) has him doing it the second way (writing it vertically) for easier problems, too. (23x4, 36x3, etc.) Can someone give me your thoughts on these different ways? If I teach him the second way, am I going to totally confuse him?

 

Thanks!

      

        

[kiana]

The first way is just a more compact version of the second way. I don't think it'd be really confusing to say "hey, the way I've been showing you multiplication -- let's write in an extra step here"

[boscopup]

Math Mammoth teaches the long way (your second option) shortly before teaching the standard algorithm. I think the point is to understand exactly what you're doing before learning the standard algorithm. I don't have Miquon, but I'll bet it teaches the standard algorithm eventually.

[Guest]

How come when you guys say it, it makes me :blushing:

 

and when I first saw the problem I was like :willy_nilly:

 

I hope I don't totally screw my kids up in this homeschooling adventure, lol.

[Crimson Wife]

It's called the "partial products" method and is in MM. The point is to make clear to the child WHY the standard algorithm works.

 

I've seen a similar method in algebra books using tiles to show why the FOIL method works.