Download Method 2: Partial Products Algorithm, This is used to test on the

Dear Families,
To help our students succeed throughout their multiplication unit, I present four different strategies for solving
multiplication problems. It is up to your child to pick the method that works best for him or her. DON’T WORRY if you
don’t understand how a particular method works. You can help support your child using ANY of these methods. The
most important thing is that your child finds something that works for him or her. Each of these methods will be shown
using the problem 42 x 39. (The distributive property was talked about in class but not in the book so the students may
not remember doing this method.)
Method 1: Traditional This is the one you should recognize!
42
X 39
378
+126
1,638
Method 2: Partial Products Algorithm, This is used to test on the MEAP.
42
X 39
1200 (30 x 40)
60 (30 x 2)
360 (9 x 40)
+ 18 (9 x 2)
1,638
Multiply each number by its place value, not just the number.
For example, 3 in this problem is really 30, or 3 tens.
After the students become good at recognizing what the partial products are
in parenthesis, they don’t need to write them down.
Method 3: Distributive Property
This is also tested on the MEAP. You look at the numbers in the problem
and see how they could be broken up to make the problem easier to do in your head.
The problem is still 42 x 39 but it is broken up into groups of tens and ones. This is similar to the partial products
algorithm.
This method can solve the same problem in various ways. For example, you could also break 42 x 39 this way:
(40 x 30) + (40 x 9) + (2 x 30) + (2 x 9) =
1200 + 360 + 60 + 18 =1,638
Method 4: The Lattice
This is a strategy that helps visual learners organize their work. Students must
multiply all numbers where they intersect and then add on diagonals. Be careful to carry over to the next diagonal
when adding. Then rewrite the numbers that are outside of the lattice on the left and bottom.
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