Lattice Multiplication and Khan Academy

Have you all seen Khan Academy? There is a lot of buzz going on about it, so I decided to try it out with our current multiplication unit and came across several videos of interest.

One I really enjoyed taught Lattice Multiplication. I had watched it the other day and loved several things about it:

• different colors on a simple black background
• it was only 7 1/2 minutes in length-- perfect!
• Sal Khan is a clear speaker with a laid-back, but engaging, voice

Check out the video here:


I hooked up my laptop to our projector and had kids in the meeting area with a white board, dry erase markers, and the new erasers I made (um, I cut out small squares of black fleece, but the kids love it and they do the job, so it's perfect!).

We started Lattice Multiplication last week for two days, but only got as far as 3 digit times one digit, so the concept of extra rows was new. I definitely paused a lot as we went through and had the kids copy the problem and how to solve onto their own whiteboards. By the last problem, I had the kids work on it for a minute or two, then compare their work to Khan's.

We also made a prediction about what place value our product would be-- many thought hundred thousands and a few thought millions, so it was exciting for them to see it was such a huge number.

Hard at work with Khan on their own white boards

Such a simple screen-- it really made it clear to understand and follow along!

I think it was a fun activity to introduce larger numbers in multiplication. It mixed it up a bit and for their ticket to leave the meeting area, I had them solve a 3 digit times 2 digit problem that I put on the board-- I was very impressed with their quick calculation time!

Have fun looking around the website-- there is a whole section on Art History that looks fascinating!