What is 4/39 plus 9/13? (Answer: 31/39)

Exact Answer

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Problem: What is 4/39 plus 9/13?
Formula / Expression: 4/39 + 9/13
Final Answer: 31/39
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
Notice that 39 is an exact multiple of 13 (13 × 3 = 39). The Least Common Denominator (LCD) is simply 39, meaning we only need to scale one fraction.
Working: LCD(39, 13) = 39

Step 2: Convert to Equivalent Fractions with Common Denominator 39
Multiply the numerator and denominator of 4/39 by 1, and multiply the numerator and denominator of 9/13 by 3 so both fractions share the common base 39.
Working: 4 × 1/39 × 1 = 4/39 and 9 × 3/13 × 3 = 27/39

Step 3: Add the Numerators
Now add the numerators (4 + 27 = 31) and keep the common denominator 39 unchanged.
Working: 4 + 27/39 = 31/39

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 31 and 39 is 1, confirming that 31/39 cannot be reduced further—it is already in its simplest irreducible form.
Working: 31/39

Step 5: Decimal & Percentage Representation
Dividing the numerator 31 by denominator 39 produces a repeating decimal (approximately 0.794872, or 79.4872%).
Working: 31 ÷ 39 = 0.794872 (79.4872%)

Key Values:
- Simplified Fraction: 31/39
- Mixed Number Form: 31/39
- Decimal Value: 0.794872
- Percentage: 79.4872%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-4-39-plus-9-13/
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4/39 + 9/13 = 31/39

Simplified Fraction

31/39

Mixed Number

Proper (31/39)

Decimal Value

0.794872

Percentage

79.4872%

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Step-by-Step Solution: 4/39 + 9/13

Step 1

Find the Least Common Denominator (LCD)

Notice that 39 is an exact multiple of 13 (13 × 3 = 39). The Least Common Denominator (LCD) is simply 39, meaning we only need to scale one fraction.

LCD(39, 13) = 39

Step 2

Convert to Equivalent Fractions with Common Denominator 39

Multiply the numerator and denominator of 4/39 by 1, and multiply the numerator and denominator of 9/13 by 3 so both fractions share the common base 39.

4 × 1/39 × 1 = 4/39 and 9 × 3/13 × 3 = 27/39

Step 3

Add the Numerators

Now add the numerators (4 + 27 = 31) and keep the common denominator 39 unchanged.

4 + 27/39 = 31/39

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 31 and 39 is 1, confirming that 31/39 cannot be reduced further—it is already in its simplest irreducible form.

31/39

Step 5

Decimal & Percentage Representation

Dividing the numerator 31 by denominator 39 produces a repeating decimal (approximately 0.794872, or 79.4872%).

31 ÷ 39 = 0.794872 (79.4872%)

Visual Representation

The diagram below illustrates 4/39 plus 9/13 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`31/39`
Mixed Number Form	`31/39`
Decimal Form	`0.794872`
Percentage	`79.4872%`

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Frequently Asked Questions

What is 4/39 plus 9/13 as a fraction?

4/39 + 9/13 in simplest fraction form is 31/39.

What is 4/39 plus 9/13 as a decimal?

4/39 + 9/13 converted to a decimal is 0.794872.

What is 4/39 plus 9/13 as a percentage?

4/39 + 9/13 expressed as a percentage is 79.4872%.

Does 4/39 plus 9/13 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.794872...) because the denominator contains prime factors other than 2 and 5.