Solve Mixed Number Addition: 2 7/9 + 1 1/3 Step-by-Step

Mixed Number Addition with Common Denominators

279+113= 2\frac{7}{9}+1\frac{1}{3}=

❤️ 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
00:00 Solve
00:03 First, convert mixed fractions to fractions
00:47 Multiply to find the common denominator
00:58 Add using the common denominator
01:06 Now convert to a mixed fraction
01:10 Break down 37 into 36 plus 1
01:16 Break down the fraction into whole number and remainder
01:22 Convert proper fraction to whole number, and combine with mixed fraction
01:30 And this is the solution to the question

Step-by-step written solution

Follow each step carefully to understand the complete solution
1

Understand the problem

279+113= 2\frac{7}{9}+1\frac{1}{3}=

2

Step-by-step solution

Let's solve the problem by converting the mixed numbers into improper fractions, finding a common denominator, and adding the fractions.

Step 1: Convert Mixed Numbers to Improper Fractions
- 2792\frac{7}{9} becomes 2×9+79=18+79=259\frac{2 \times 9 + 7}{9} = \frac{18 + 7}{9} = \frac{25}{9}.
- 1131\frac{1}{3} becomes 1×3+13=3+13=43\frac{1 \times 3 + 1}{3} = \frac{3 + 1}{3} = \frac{4}{3}.

Step 2: Find a Common Denominator
- The denominators are 9 and 3. The least common denominator is 9.

Step 3: Convert Fractions to a Common Denominator
- 259\frac{25}{9} is already with the denominator 9.
- 43=4×33×3=129\frac{4}{3} = \frac{4 \times 3}{3 \times 3} = \frac{12}{9}.

Step 4: Add the Fractions
259+129=25+129=379\frac{25}{9} + \frac{12}{9} = \frac{25 + 12}{9} = \frac{37}{9}.

Step 5: Convert the Improper Fraction Back to a Mixed Number
- 379 \frac{37}{9} is 4194 \frac{1}{9} because 37 divided by 9 is 4 with a remainder of 1.

Therefore, the solution to the problem 279+113 2\frac{7}{9}+1\frac{1}{3} is 419 4\frac{1}{9} .

3

Final Answer

419 4\frac{1}{9}

Key Points to Remember

Essential concepts to master this topic
  • Rule: Convert mixed numbers to improper fractions before adding
  • Technique: Find LCD by identifying multiples: LCD of 9 and 3 is 9
  • Check: Convert final answer back to mixed number: 379=419 \frac{37}{9} = 4\frac{1}{9}

Common Mistakes

Avoid these frequent errors
  • Adding whole parts and fraction parts separately without converting
    Don't just add 2+1=3 and 79+13 \frac{7}{9} + \frac{1}{3} separately = wrong answer like 319 3\frac{1}{9} ! This ignores proper fraction conversion and gives incorrect results. Always convert mixed numbers to improper fractions first, then add with common denominators.

Practice Quiz

Test your knowledge with interactive questions

\( 5:\frac{2}{5}= \)

FAQ

Everything you need to know about this question

Why can't I just add the whole numbers and fractions separately?

+

While it seems easier, you need a common denominator for the fraction parts! In this problem, 79+13 \frac{7}{9} + \frac{1}{3} requires converting 13 \frac{1}{3} to 39 \frac{3}{9} first.

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

+

Use the formula: multiply whole number by denominator, then add numerator. For 279 2\frac{7}{9} : (2 × 9) + 7 = 18 + 7 = 259 \frac{25}{9}

What's the easiest way to find the LCD of 9 and 3?

+

Since 9 is a multiple of 3 (9 = 3 × 3), the LCD is simply 9! When one denominator divides evenly into the other, the larger number is always the LCD.

How do I convert the improper fraction back to a mixed number?

+

Divide the numerator by the denominator. For 379 \frac{37}{9} : 37 ÷ 9 = 4 remainder 1, so the answer is 419 4\frac{1}{9} .

Can I solve this problem without converting to improper fractions?

+

Yes, but it's more complicated! You'd add whole numbers (2+1=3), then add fractions with common denominator (79+39=109 \frac{7}{9} + \frac{3}{9} = \frac{10}{9} ), then convert 109 \frac{10}{9} to 119 1\frac{1}{9} and add to get 419 4\frac{1}{9} . Converting to improper fractions is usually cleaner!

🌟 Unlock Your Math Potential

Get unlimited access to all 18 Mixed 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