Multiplying fractions is easy
Multiplying fractions is an impressively easy topic!
In this article, you will learn in no time how to solve any fraction multiplication exercise.
Shall we start?
The method to solve fraction multiplications is - numerator by numerator and denominator by denominator.
Let's remember this method as this is how we will proceed in all the fraction multiplication exercises.
Important observations:
- The commutative property works - as it is a multiplication exercise, the commutative property acts the same way with fractions, and if we change the order of the parts of the exercise, the result will not be altered.
- If we come across the multiplication of a fraction by a whole number or by a mixed number, we will first convert that number to a fraction.
Let's start solving and, little by little, we will see all the possibilities along the way.
Multiplication of Fraction by Fraction
Fraction by fraction multiplication exercises are very simple and are solved by multiplying numerator by numerator and denominator by denominator.
For example
32βΓ53β=156β
Solution:
We multiply the numerator 3 by the numerator 2 and obtained 6 in the numerator.
We multiply the denominator 5 by the denominator 3 and obtained 15 in the denominator.
We can simplify and arrive at 52β
Another exercise
21βΓ92βΓ31β
Solution:
We will multiply the numerator by the numerator by the numerator -> 1Γ2Γ1=2
and the denominator by the denominator by the denominator 2Γ9Γ3=54
We will obtain
542β
We can simplify and get toβ 271β
Observe - Since this is a multiplication exercise we can apply the commutative property and change the order of the fractions writing them, for example, in the following way - >21βΓ31βΓ92β, the result will not vary.
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Multiplication of an Integer by a Fraction
When we have an exercise with an integer that is multiplied by a fractional number, we will convert the integer to a fraction and then proceed to solve according to the method of numerator by numerator and denominator by denominator.
How do you convert an integer to a fraction? It's very easy!
You can convert any number to a fraction in the following way: write the given number in the numerator
and in the denominator write 1.
For example
2=12β
7=17β
Now let's practice this:
3Γ62β=
Solution:
First, let's convert the whole number to a fraction:
31β=3
Now let's write the exercise only with fractions:
62βΓ13β=
Let's solve using the method we learned - Numerator by numerator and denominator by denominator, we will get: 66β that is, 1.
Fraction by mixed number
We will solve multiplication exercises of fractions by mixed numbers like this:
We will convert the mixed number to a fraction.
Now we can solve using the method of numerator by numerator and denominator by denominator.
What is a mixed number?
A mixed number is, in fact, a fraction composed of a whole number and a fraction, like, for example 354β.
How do you convert a mixed number to a fraction?
Multiply the whole number by the denominator.
Then add the numerator, and this will be the number that will be written in the place of the numerator.
For example
Convert the mixed number 432β to a fraction.
Solution: We will multiply the whole number by the denominator and add the numerator
4Γ3+2=
12+2=14
The obtained number (14) will be written in the numerator, while the denominator will not change.
This gives us:
432β=314β
Now let's practice multiplying a mixed number by a fraction:
43βΓ292β=
Solution:
First, we will convert the mixed number to a fraction:
We will do it the way we learned 2Γ9+2=20
We will write the result in the numerator and the denominator will remain the same. We obtain: 209β
Let's rewrite the exercise:
43βΓ920β=
Multiply numerator by numerator and denominator by denominator, we will obtain:
3660β=35β
Do you know what the answer is?
Multiplication of an Integer by a Mixed Number
To solve exercises of multiplying an integer by a mixed number, we will convert both numbers to simple fractions, then proceed according to the method of numerator by numerator and denominator by denominator.
Example
5Γ132β
Let's convert the whole number 5 to a fraction -> 15β
Let's convert the mixed number 312β to a fraction -> 35β
Let's rewrite the exercise and solve by multiplying numerator by numerator and denominator by denominator:
15βΓ35β=325β
Examples and exercises with solutions for multiplying fractions
Exercise #1
41βΓ54β=
Video Solution
Step-by-Step Solution
To multiply fractions, we multiply numerator by numerator and denominator by denominator
1*4 = 4
4*5 = 20
4/20
Note that we can simplify this fraction by 4
4/20 = 1/5
Answer
Exercise #2
23βΓ1Γ31β=
Video Solution
Step-by-Step Solution
According to the order of operations rules, we will solve the exercise from left to right since there are only multiplication operations:
23βΓ1=23β
23βΓ31β=
We will multiply the three by three and get:
21βΓ1=21β
Answer
Exercise #3
32βΓ75β=
Video Solution
Answer
2110β
Exercise #4
43βΓ21β=
Video Solution
Answer
Exercise #5
41βΓ21β=
Video Solution
Answer