Let's see an example:
Xร2=2รX
We can replace the X with a number:
X=3
We get:
2ร3=6
3ร2=6
As you can see, it doesn't matter in what order we multiply the factors, we still get the same correct answer.
Note that the commutative property of multiplication does not work with division.
Starting to get it? Keep practicing to turn this new property into muscle memory.
Exercises with the commutative property of multiplication
Exercise 1
Task:
5.25โ
32โโ
217โ=?
Solution:
First, we convert the decimal number into a mixed fraction.
541โโ
32โโ
217โ=
Then, we convert the mixed fraction into a simple fraction.
45ร4+1โโ
32โโ
217โ=
421โโ
32โโ
217โ=
Notice that you can reduce to 21 and get a simpler expression.
47โโ
32โ=
We multiply the numerator by the numerator and the denominator by the denominator.
4ร37ร2โ=
1214โ=
We continue to reduce as much as possible.
1122โ=
161โ
Answer:
161โ
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Exercise 2
Task:
441โโ
394โโ
3171โ=?
Solution:
First, we convert all mixed fractions to simple fractions.
44ร4+1โร93ร9+4โร173ร17+1โ=
416+1โร927+4โร1751+1โ=
417โร931โร1752โ=
We reduce to 17
452โร931โ=
We divide 52 by 4 and solve
13ร931โ=
9403โ=4497โ
Answer:
4497โ
Exercise 3
Task:
(7+2+3)(7+6)(12โ3โ4)=?
Solution:
We start by solving each of the parentheses in the order of operations.
(9+3)ร13ร(9โ4)=
12ร13ร5=
We move the 5 to the left so that we can easily solve the exercise from left to right
12ร5ร13=
60ร13=780
Answer:
780
Do you know what the answer is?
Exercise 4
Task:
5โ
7โ
13โ
6=?
Solution:
We reorder the exercise into two smaller expressions so that they are simpler to solve.
7โ
13โ
6โ
5=
We start by solving the first expression in the exercise, and then the second.
Then we solve the whole, simplified expression.
91โ
30=2730
Answer:
2730
Exercise 5
Task:
5โ
17โ
2=?
Solution:
We reorder the exercise to make it easier to solve.
5โ
2โ
17=
We continue solving the exercise from left to right.
10โ
17=170
Answer:
170
Review questions
What is the commutative property in multiplication?
The commutative property of multiplication tells us that changing the order of the factors in an expression won't change the end result
For example, we will get the same answer if we multiply 3ร16 or if we multiply 16ร3, in both cases the result is 48.
How does the commutative property work in multiplication?
The commutative property in multiplication can be understood as follows: aรb=bรa
This means that the order of the factors does not change the result. If we assign values to a=4 and b=6, applying the commutative property we will get:
4ร6=24
6ร4=24
We can see that in both cases it gave us the same result even though the factors are in a different order.
What are the 4 properties of multiplication?
The 4 properties of multiplication are the following:
- Commutative: No matter the order of the factors, the result will be the same aรb=bรa
- Associative: No matter how we group sets of factors, the result will be the same. aร(bรc)=(aรb)รc
- Distributive: Multiplying a factor by the sum of two addends is the same as multiplying by each addend separately and then adding the results together. aร(b+c)=aรb+aรc
- Identity element: The identity element of multiplication is 1, because if we multiply a number by the number 1, the result will still be that number. This can be understood as follows aร1=a.
Do you think you will be able to solve it?
Examples with solutions for The Commutative Property of Multiplication
Exercise #1
Solve the following problem:
15ร2ร8=
Video Solution
Step-by-Step Solution
Since the exercise involves only multiplication, we will use the commutative property to simplify the calculation:
2ร15ร8=
Now let's solve the multiplication on the right:
15ร8=120
We obtain the following expression:
2ร120=240
Answer
Exercise #2
Solve the following exercise:
5+14+5=ย ?
Video Solution
Step-by-Step Solution
Since the exercise only involves addition, we will use the commutative property to calculate more conveniently:
5+5+14=
We will then solve the exercise from left to right:
5+5=10
10+14=24
Answer
Exercise #3
Solve the following exercise:
8+9+2=ย ?
Video Solution
Step-by-Step Solution
Since the exercise only involves addition, we will use the commutative property to solve it.
8+2+9=
Now let's solve the exercise from left to right:
8+2=10
10+9=19
Answer
Exercise #4
Solve:
โ5+4+1โ3
Video Solution
Step-by-Step Solution
According to the order of operations, addition and subtraction are on the same level and, therefore, must be resolved from left to right.
However, in the exercise we can use the substitution property to make solving simpler.
-5+4+1-3
4+1-5-3
5-5-3
0-3
-3
Answer
Exercise #5
Video Solution
Step-by-Step Solution
According to the order of operations, we first solve the division exercise:
4:2=2
Now we obtain the exercise:
2+2=4
Answer