Solve for X: 4⅓ × x = 21⅔ Mixed Number Equation

Mixed Number Equations with Isolation Methods

Solve the equation

413x=2123 4\frac{1}{3}\cdot x=21\frac{2}{3}

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Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:00 Solve the following expression
00:05 Break down the fraction
00:13 Convert the whole number into a proper fraction
00:23 Combine the fractions
00:29 Insert the solution into the exercise
00:33 Use the same method for the second number
00:37 Break down the fraction
00:45 Convert the whole number into a proper fraction
00:51 Combine the fractions
01:01 Insert the solution into the exercise
01:08 Multiply by the denominator in order to eliminate fractions
01:20 Simplify where possible
01:28 Isolate the unknown X and calculate
01:37 Here is the solution

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Solve the equation

413x=2123 4\frac{1}{3}\cdot x=21\frac{2}{3}

2

Step-by-step solution

We have an equation with a variable.

Usually, in these equations, we will be asked to find the value of the missing (X),

This is how we solve it:

To solve the exercise, first we have to change the mixed fractions to an improper fraction,

So that it will then be easier for us to solve them.

Let's start with the four and the third:

To convert a mixed fraction, we start by multiplying the whole number by the denominator

4*3=12

Now we add this to the existing numerator.

12+1=13

And we find that the first fraction is 13/3

Let's continue with the second fraction and do the same in it:
21*3=63

63+2=65

The second fraction is 65/3

We replace the new fractions we found in the equation:

13/3x = 65/3

At this point, we will notice that all the fractions in the exercise share the same denominator, 3.

Therefore, we can multiply the entire equation by 3.

13x=65

Now we want to isolate the unknown, the x.

Therefore, we divide both sides of the equation by the unknown coefficient -
13.

63:13=5

x=5

3

Final Answer

x=5 x=5

Key Points to Remember

Essential concepts to master this topic
  • Conversion: Change mixed numbers to improper fractions first
  • Technique: Convert 413 4\frac{1}{3} to 133 \frac{13}{3} using 4×3+1=13
  • Check: Substitute x=5 back: 133×5=653=2123 \frac{13}{3} \times 5 = \frac{65}{3} = 21\frac{2}{3}

Common Mistakes

Avoid these frequent errors
  • Working with mixed numbers directly without converting
    Don't try to multiply 413×x 4\frac{1}{3} \times x without converting = confusing calculations and wrong answers! Mixed numbers make multiplication and division much harder. Always convert to improper fractions first using whole×denominator+numerator.

Practice Quiz

Test your knowledge with interactive questions

Solve for X:

\( x - 3 + 5 = 8 - 2 \)

FAQ

Everything you need to know about this question

Why can't I just work with the mixed numbers as they are?

+

Mixed numbers make calculations much more complicated! Converting to improper fractions like 133 \frac{13}{3} makes multiplication and division straightforward.

How do I convert a mixed number to an improper fraction?

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Use this formula: whole × denominator + numerator. For 413 4\frac{1}{3} : 4×3+1=13, so it becomes 133 \frac{13}{3} .

Can I multiply both sides by 3 to clear the denominators?

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Absolutely! Since both fractions have denominator 3, multiplying both sides by 3 gives you 13x = 65, which is much easier to solve.

What if I get a different answer when I check?

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Go back and check your conversion step. The most common error is calculating whole×denominator+numerator incorrectly when converting mixed numbers.

Do I need to convert my final answer back to a mixed number?

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Not necessarily! Since the answer x=5 is a whole number, it's already in its simplest form. Mixed number conversion is mainly needed for fractional answers.

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