Solve the Fraction Subtraction: 5/4 - 3/8 Step-by-Step

Fraction Subtraction with Different Denominators

Solve the following exercise:

5438=? \frac{5}{4}-\frac{3}{8}=\text{?}

❤️ Continue Your Math Journey!

We have hundreds of course questions with personalized recommendations + Account 100% premium

Step-by-step video solution

Watch the teacher solve the problem with clear explanations
00:05 Let's solve this problem!
00:08 First, multiply the fraction by two. This helps us find a common denominator.
00:14 Remember, multiply both the top number, the numerator, and the bottom number, the denominator.
00:20 Now, let's calculate these multiplications.
00:24 After that, subtract using our common denominator.
00:31 Go ahead and work out the numerator.
00:35 Great job! That's how we solve this question.

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

Solve the following exercise:

5438=? \frac{5}{4}-\frac{3}{8}=\text{?}

2

Step-by-step solution

To solve this problem, we'll perform the following steps:

  • Step 1: Find the Least Common Denominator (LCD) between 4 4 and 8 8 .
  • Step 2: Convert both fractions to have this common denominator.
  • Step 3: Subtract the numerators, keeping the denominator the same.

Let's apply these steps starting with the first one.

Step 1: Find the Least Common Denominator
The denominators are 4 4 and 8 8 . The least common denominator is the smallest number that both denominators divide into evenly. In this case, the LCD is 8 8 because it is the smallest number that is a multiple of both 4 4 and 8 8 .

Step 2: Convert fractions to have the same denominator of 8 8
- The fraction 54 \frac{5}{4} needs to be converted to a denominator of 8 8 . To do this, multiply both the numerator and denominator by 2 2 :

54×22=108\frac{5}{4} \times \frac{2}{2} = \frac{10}{8}

- The fraction 38 \frac{3}{8} already has the denominator 8 8 , so it remains unchanged as 38 \frac{3}{8} .

Step 3: Subtract the numerators
Now that the fractions have the same denominator, subtract the numerators:

10838=1038=78\frac{10}{8} - \frac{3}{8} = \frac{10 - 3}{8} = \frac{7}{8}

Therefore, the solution to 5438 \frac{5}{4} - \frac{3}{8} is 78\frac{7}{8}.

3

Final Answer

78 \frac{7}{8}

Key Points to Remember

Essential concepts to master this topic
  • LCD Rule: Find common denominator before subtracting fractions
  • Technique: Convert 54 \frac{5}{4} to 108 \frac{10}{8} by multiplying by 22 \frac{2}{2}
  • Check: Verify 10838=78 \frac{10}{8} - \frac{3}{8} = \frac{7}{8} makes sense ✓

Common Mistakes

Avoid these frequent errors
  • Subtracting numerators and denominators separately
    Don't subtract 5438 \frac{5}{4} - \frac{3}{8} as 5348=24 \frac{5-3}{4-8} = \frac{2}{-4} ! This gives a completely wrong negative answer. Always find the LCD first, then convert both fractions to equivalent forms with the same denominator.

Practice Quiz

Test your knowledge with interactive questions

Solve the following exercise:

\( \frac{3}{2}-\frac{1}{2}=\text{?} \)

FAQ

Everything you need to know about this question

Why can't I just subtract 5-3 and 4-8 separately?

+

Because fractions represent parts of a whole! You can only subtract fractions when they have the same denominator - like subtracting 3 apples from 10 apples, not 3 oranges from 5 apples.

How do I find the LCD of 4 and 8?

+

List the multiples: 4: (4, 8, 12...) and 8: (8, 16, 24...). The smallest common multiple is 8, so that's your LCD!

What if both fractions need to be converted?

+

Convert both fractions to have the LCD as denominator. For example, if LCD is 12, change 13 \frac{1}{3} to 412 \frac{4}{12} and 14 \frac{1}{4} to 312 \frac{3}{12} .

Do I need to simplify my final answer?

+

Always check if your answer can be simplified! Look for common factors in numerator and denominator. In this case, 78 \frac{7}{8} is already in simplest form.

What if I get a mixed number as my answer?

+

If your answer is an improper fraction (numerator larger than denominator), you can convert it to a mixed number by dividing. But both forms are correct!

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Operations with Fractions questions, detailed video solutions, and personalized progress tracking.

📹

Unlimited Video Solutions

Step-by-step explanations for every problem

📊

Progress Analytics

Track your mastery across all topics

🚫

Ad-Free Learning

Focus on math without distractions

No credit card required • Cancel anytime

More Questions

Click on any question to see the complete solution with step-by-step explanations