Video Transcript
Commutative Property of
Multiplication
In this video, we will learn how to
identify and apply the commutative property of multiplication to multiply numbers up
to 10 times 10 in any order.
What is the commutative property of
multiplication? It tells us that we can multiply
factors in any order and the product will stay the same. Here are six chicks arranged into
two groups of three. We know that two times three equals
six. Two and three are factors of
six. These are the numbers we multiply
together to make six. So we can say that six is the
product of two and three. We’ve learned that the commutative
property of multiplication tells us that we can multiply factors in any order and
the product will stay the same.
So if two times three equals six,
we know that three times two equals six. It doesn’t matter if we have two
groups of three or three groups of two; the product is still six.
In the same way, if we arrange 15
squares into five groups of three to show that five times three equals 15, we can
also arrange our 15 squares into three groups of five. Three and five are factors of
15. And we know the commutative
property of multiplication tells us, “It doesn’t matter which order we multiply the
factors; the product stays the same.” Five times three equals 15, and
three times five equals 15.
We can use arrays to show how the
commutative property of multiplication works. This array shows eight rows of
four. We can find the product of eight
and four by counting in fours eight times. Here we go. Four, eight, 12, 16, 20, 24, 28,
32. Eight times four is 32. If we change the order of the
factors, the product stays the same.
Let’s put into practice what we’ve
learned about the commutative property of multiplication by answering some questions
now.
Use less than, equal to, or
greater than to fill in the blank: Four times six what six times four.
In this question, we have to
fill in the blank to make the statement correct. Is four times six less than six
times four or is four times six equal to six times four or is four times six
greater than six times four? Let’s use an array to help us
calculate four times six. This array has four rows of
six. We know that one row of six or
one times six is six, two times six is 12, three times six is 18, four times six
is 24. So what is six times four? This array shows six rows of
four.
Let’s count in fours to find
six times four. Four, eight, 12, 16, 20,
24. Four and six are factors of
24. It doesn’t matter which order
we multiply the factors; the product stays the same. This question is all about the
commutative property of multiplication. It doesn’t matter which order
we multiply the factors; the product stays the same. Four times six is equal to six
times four. The missing symbol is equal
to.
Complete: eight times five
equals five times what.
We have to find the missing
number in this equation. Because there’s an equal sign
in the middle, we know that eight times five is equal to five multiplied by our
missing number. This array shows eight rows of
five counters. Let’s count in fives to find
the total number of counters. Five, 10, 15, 20, 25, 30, 35,
40. So we know that eight times
five is 40. And if we turn our array the
other way round to show five rows of eight, then the product will be the
same. Eight rows of five are 40, and
five rows of eight are 40. The missing number is
eight. We know that we can multiply
eight and five in any order; the product will still be 40. Eight times five is equal to
five times eight.
Madison is skip counting to
find five times four. Four, eight, 12, 16, 20. How else could she skip count
to find five times four? Two, four, six, eight, 10, 12,
14, 20. Two, four, eight, 12, 16,
20. Five, 10, 15, 20. Five, seven, 10, 14, 20. Which other equation would this
solve? Four times four, four plus
five, five times five, or four times five.
In this question, Madison is
skip counting to find five times four. She counted in fours five
times. Four, eight, 12, 16, 20. We have to find another way to
skip count to find five times four. Madison skip counted in fours
five times to find five times four. What would happen if we changed
the order of the two numbers we’re multiplying? Instead of finding five times
four, we could find four times five. We’d need to count in fives
four times. Five, 10, 15, 20.
The product is the same. So although our first possible
answer takes us to the number 20, it doesn’t show five times four or four times
five. Two, four, six, eight, 10, 12,
14, 20. It looks like someone was skip
counting in twos, but they did leave out the numbers 16 and 18. So this isn’t a way of skip
counting to show five times four. Two, four, eight, 12, 16,
20. This doesn’t show five times
four. We start off by skip counting
in twos and then in fours. So we can eliminate this
answer. Five, 10, 15, 20. This is four times five, skip
counting in fives four times. This is another way Madison
could skip count to find five times four.
Which other equation would this
solve? Four times four, four plus
five, five times five, or four times five. If five times four equals 20,
then four times five equals 20. This question is all about the
commutative property of multiplication. It doesn’t matter which order
we multiply two factors; the product stays the same. If five times four is 20, then
four times five is 20.
What have we learned in this
video? We have learned how to identify and
apply the commutative property of multiplication to multiply numbers up to 10 times
10 in any order.
