Nine Facts

There are two main strategies for the nine facts, and a secondary one.  Of these , I like the ten fact connection the best as it uses more number sense and builds on other facts.  The patterning is fairly effective.

Patterning

The more common is to use two patterns in the nines facts.

a. The first digit of the product is always one less than the number of nines you have.  For example, for 6 X 9, the answer starts with a 5 (one less than 6).
b.

The two digits in the product always add to nine. 

For example, for 3 X 9 = 27, 2 + 7 = 9.

Used together, these two patterns let you figure out the product if you can’t remember.  There are many other patterns in the nines facts.  A great way to approach this topic is to have students discover all the patterns they can, and then point out the usefulness of these two.

Ten Fact Connection

Another strategy is to use the ten times facts when they have been learned. 6 X 9 is 7 less than 6 X 10.  This is best demonstrated pictorially to students.

Finger Strategy

I’m really starting to dislike the finger strategy. It doesn’t use any number sense, and I find students have trouble moving on from it.  Basically, it’s a procedure that will show them the answer, but doesn’t really help them make connections.  I’ve seen students in grade 8 using this strategy, which shows they haven’t moved to automaticity.

 

Resources


Nines flash cards 

These cards indicate to students that there is a relationship between the number of groups and the first digit of the product, as well as between the two digits of the product.

Nine times multiplication facts flash cards

Nines Patterning Lesson 

Full lesson for discovering patterns in the nines facts.

Comments

  1. I dont liky

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