You may not explicitly teach the 11’s facts if your curriculum expects you to only teach to 10×10. However, the 11’s facts are a great opportunity to reinforce the conceptual idea of using what you know and then adding a group.
So, for example, for a fact like 11×5, you can first think 10×5=50, and then add another group of 5 to make 55.
Or for a fact like 11×7, you could start with 10×7 to make 70, then add another group of 7 to make 77.
It’s also very important to reinforce the commutative property.
This means that the order of factors does not change the product. For example, if students are faced with an equation like 7×11, they should see the 11 as one of the factors, and know that they can use this “add a group” strategy to solve this equation.
Teaching the 11’s as “the same number twice” is a common trick. For example, 5×11 will be a “5” twice to make 55. 8×11 will be an “8” twice to make 88.
This does work, but it is limiting because it only works up to 11×9.
When we focus on strategy, rather than a limiting trick, we enable our students to solve ANY problem – not only those that fit into a certain span of numbers. For example, if we are faced with the problem 11×14, we know that we can simply multiply 10×14 to make 140 then add another group of 14 to make 154. The “same number twice” trick does not enable us to solve a problem like this.
NEXT STEPS
Reinforce the 11’s multiplication facts with this set of task cards. Students will learn conceptually through problem-solving, using arrays, strategic thinking, finding missing numbers, skip-counting, picture representations, and more:
OR FIND THE FULL BUNDLE OF MULTIPLICATION TASK CARDS HERE.
OTHER HELPFUL RESOURCES
Multiplication Strategy Posters
Multiplication Equation of the Day: Multiplication Fact Booklets
The Multiplication Station: a Self-Paced Program for Mastering the Basic Multiplication Facts
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