Strategies+to+master+multiplication+facts

From:http://olc.spsd.sk.ca/de/math1-3/p-mentalmath.html#basicmult The basic number facts are among the tools that students need to be successful in their mathematics program. In the past, students memorized the facts once they had been introduced to Multiplication as a faster method of addition. Before these strategies are taught, students must gain a complete understanding of the concept of multiplication. They should actually make groups of things and relate these groups to the number facts. They should skip count and make arrays to gain a complete understanding of multiplication. If you have zero groups of anything you have nothing. It is fun to teach this by offering several different groups of zero to students. “Here, you can have zero Smarties. How many did you get? zero Work through several examples. The idea is that it doesn’t matter how many numbers are in a set or group, if you have zero sets you have nothing. So 1 x 0 is 0 one group of zero and 0 x 1 = 0 zero groups of one = zero
 * Strategies for Basic Multiplication Facts**
 * Now it is recommended that students learn patterns and strategies for as many facts as possible so that they strengthen their understanding of the relationships between numbers and the patterns in mathematics.** Then they begin to memorize. There are many strategies out there. Here are some that have been successful with many students.
 * Multiply by zero**

Once students understand this they will never have to practice it. Students may as well learn this right away. If you have 2 groups of zero or zero groups of two, you have the same amount. Work through several examples with zero to be sure that students understand. Then, review this with all the other strategies as all facts have a turn around fact. Again this is a concept that students need only to understand and then they will always know the one times facts. One times any number means one group of that number which is the same number.
 * Commutative Property (Turn around facts)**
 * Multiplying by one**

1 x 6 is one group of six = six Turn around fact; 6 groups of one = 6 x 1 = 6 If students do lots of examples to gain this understanding, they will not have to practice this. This is just double numbers, which they should already be familiar with.
 * Multiply by Two**

For example: 2 x 8 = 8 + 8 = 16 It would take a couple of lessons to work through examples where you relate the two ideas and give students a chance to practice. Then they should be able to use this strategy. A hundreds board works great for this as do base ten rods. Students need to make groups of tens. They will see the pattern fairly quickly but they need to see the number pattern of increasing by ten as well as the “adding zero” factor. Once they explore with groups of ten then they can use the rule of adding zero to multiply 10 by any number. Again, they should review the turn around fact as well. Two groups of ten = 20 10 groups of 2 = 20 Counting by fives is a common factor in our society so multiplying by fives can fit right in here. Use a clock to introduce the five times table.
 * Multiply by Ten**
 * Multiply by five**

We talk about 5 after, ten after, fifteen after – so this is one group of five, two groups of five, etc. Have students count by fives and review the zero – five pattern 5, 10, 15, 20 (ends in zero, ends in five).

Work with examples like these to help children find patterns in the five times table and then remind them of the turn around facts.

There are several ways to help students with this but the neatest one is that there is a nifty pattern to the nines. If students look at some examples: one group of nine is 9. Two groups of nine is 18, three groups of nine is 27 they can see that the answer adds up to nine and the tens digit is one less than the factor the nine is being multiplied by. Correspondingly the last digit, when added to the factor makes ten. For example: 4 x 9 – the first digit is one less than 4 (the factor) and the last digit will add up to 9 if added to the first digit. Also, the factor 4 and the last digit will add up to ten. Those are some basic strategies that along with the turn around strategies help give students a solid base on which to build their multiplication facts. The Nelson program also teaches students to build new facts from known facts. For example: If a child knows 5 x 3 = 15 they can figure out 6 x 3 = 18 (one more group of 3) If a child knows 6 x 7 = 42 then 7 x 7 = one more group of seven = 49 This can be used on facts with 5’s and 10’s.
 * Multiplying by 9**
 * It is confusing until you try it out several times and then the pattern appears much more simple.**
 * Halving strategies**

If a child knows 8 x 5 = 40 she can halve and double to find 4 x 10 = 40. (half of 4 and double 5)

Another example; 4 x 5 = 20 half and double 2 x 10 = 20.