Strategies for Multiplication Facts

advertisement
Strategies for Multiplication
Facts
Some Easy Tips
 0 times any number equals 0.
 1 times any number equals that number.
 2 times any number is double the number.
 5 times a number always ends in either 5 or o; even
numbers times 5 end in 0, odd numbers times 5 end
in 5.
 10 times a number is the same number with a 0 at
the end.
Skip Counting
 Students have been practicing skip counting since 1st
Grade. By 3rd Grade, this ability to skip count helps
when mastering the multiplication facts for 2s, 3s,
5s, 10s.
Skip Counting
 For example, when we skip count by 3s, the pattern
that develops looks like this:
3
Skip Counting
 For example, when we skip count by 3s, the pattern
that develops looks like this:
3
6
Skip Counting
 For example, when we skip count by 3s, the pattern
that develops looks like this:
3
6 9
Skip Counting
 For example, when we skip count by 3s, the pattern
that develops looks like this:
3
6 9 12
Skip Counting
 For example, when we skip count by 3s, the pattern
that develops looks like this:
3
6 9 12 15
Skip Counting
 For example, when we skip count by 3s, the pattern
that develops looks like this:
3
6 9 12 15
and so on…
Skip Counting
 When we multiply by 2, the answers follow the same
pattern.
3x1=3
3x2=6
3x3=9
3 x 4 = 12
3 x 5 = 15
3 6 9 12 15
and so on…
Counting Up or Down from a Known Fact
This strategy involves skip counting once or twice from
a known fact. For example, if a child knows
5 x 5 is 25, then this can be used to solve 5 x 6 (5 more
or 30) or 5 x4 (5 less or 20).
Doubling
Some children use doubling relationships to help them
with multiplication facts involving 4s, 6s, and 8s,
For example, 4 times 7 is twice as much as 2 x 7.
Since 2 x 7 =14, it follows that 4 x 7 is 28.
Finding Other Patterns:
The Nines
When the answers to
the multiplication
facts for nine are
listed in a column, it
is easy to see that the
digits in the tens
palace count up by
one and the digits in
the ones place, count
down by one.
9x1=
9x2=
9x3=
9x4=
9x5=
9x6=
9x7=
9x8=
9x9=
9
18
27
36
45
54
63
72
81
Those Pesky 4s, 6s, 7s, 8s
 Although there are no specific tricks for remember
the facts for 4s,6s, 7s and 8s, other than Doubling
or Counting Up or Down from a Known Fact,
the Commutative Property of Multiplication
will help children realize that they do not have as
many facts to remember for these numbers as they
think.
The Commutative Property: A Big Term for Any Easy
Concept
 Commutative property: The wording of this
may seem like it would be a difficult concept to
learn, but actually it is quite easy.
 It simply means that when two numbers are
multiplied together, the product (or answer) is the
same regardless of the order of the numbers being
multiplied. For example 4 x 2 is the same as 2 x 4:
2x4 =8
4x2 =8
Those Pesky 4s, 6s, 7s, 8s
 Students who learn the Commutative Property
of Multiplication will realize that they already
know many of the facts for these numbers. For
example:
 6 x 0, 6 x 1, 6 x 2, 6 x 3, 6 x 5, 6 x 9, 6 x 10 are facts
they have already learned.
 They only then need to learn 6 x 4, 6 x 6, 6 x 7, and
6 x 8; and they probably have already learned 6 x 4,
when they learned the facts for the number 4.
Making Arrays
 For those students who still are struggling with
understanding that multiplication is simply repeated
addition, or a quicker way to add numbers, creating arrays
is very helpful. Click on the link to learn about and practice
arrays:
 http://www.haelmedia.com/OnlineActivities_txh/mc_txh3
_002.html
 Click to allow this site to open. When the site is accessed,
click on Continue twice, then click on the
Multiplication Fact link.
Download