Multiplication Strategies

For the intervention part of the day, we've been working on multiplication.  The fifth grade standard says students have to solve using the US standard algorithm, but we are stressing multiple ways to calculate the product.

I give my students a warm up problem, have them work independently for a few minutes, then share with a neighbor how they solved the problem.  If the group got different answers, they work together to solve it again, thus practicing their math discourse.  (Also, mathematical practice #3 about critiquing the reasoning of others).

Here's a snapshot of one group's work:

The strategies they typically use are:

1. US standard algorithm

2. British standard algorithm (very similar to US but with more of an emphasis on place value, as seen in the top image)

3. Partial Products

4. Estimation or compatible numbers to check for reasonableness

5. Repeated addition

6. Halves & Doubles

7. Lattice Method

I love that they're focused on the process of finding the answer rather than the one right answer.  It lends itself to much richer mathematical discussions about the value of numbers.