A few of my kiddos are still really struggling with multiplication - stemming from the fact that they have yet to memorize their math facts. They understand the algorithm ... it's just the knowledge of the facts that are holding them back ... and I'm doing everything I can to help them get there (wish I could go home with a few of them to make sure they are practising at home, too). Anyhow ... I digress ... sigh ...
I stumbled across a neat picture on pinterest this weekend. It wasn't linked back to a blog that I can credit - just a website full of random pictures. I was intrigued, though, and knew right away it was something I was going to try with my students.
This is it ... don't worry - it's not as confusing as it first looks. I colour coded the example so you can see what we did. You start with vertical lines - the three green lines on top represent the 3 tens in 32, the two red lines below show the two ones. Then you do horizontal lines - two brown lines for the 2 tens in 25, and 5 blue lines for the 5 ones.
Going diagonally, you group where the lines intersect. The group in the top left, then the middle groups, then the bottom right - since there are three groups of intersecting lines, there are three place value columns. Count all the intersections in each group - in this case, there were 6 in the hundreds, 19 in the tens, and 10 in the ones. We recorded the numbers in a place value chart. After regrouping the place value columns, our answer showed 800 - the same answer we got when doing the standard algorithm.
I then asked students to pair up and create their own 2 digit by 2 digit multiplication question. They had to solve it with the standard algorithm and the "plaid" picture. They loved it! And I LOVED the math talk that was happening.
Do you see those green dots in the corner of the pages? I asked my students to code their papers with a traffic light comprehension dot - guess they were feeling pretty successful today - we were ALL green! GO GREEN!
One of my pairs got so into it that they wanted to stay in at recess to keep exploring - they tried numbers with decimals and some 3-digit by 3-digit. They didn't quite figure out the decimal numbers, but they worked away at the 3-digit multiplication and solved it! Talk about perseverance and initiative!
For homework tonight, I asked the students to "teach" their parents or an older sibling about this strategy. I can't wait to hear the stories they'll share tomorrow!