What is 10/39 plus 9/13? (Answer: 37/39)

Exact Answer

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Problem: What is 10/39 plus 9/13?
Formula / Expression: 10/39 + 9/13
Final Answer: 37/39
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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 10/39 by 1, and multiply the numerator and denominator of 9/13 by 3 so both fractions share the common base 39.
Working: 10 × 1/39 × 1 = 10/39 and 9 × 3/13 × 3 = 27/39

Step 3: Add the Numerators
Now add the numerators (10 + 27 = 37) and keep the common denominator 39 unchanged.
Working: 10 + 27/39 = 37/39

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 37 and 39 is 1, confirming that 37/39 cannot be reduced further—it is already in its simplest irreducible form.
Working: 37/39

Step 5: Decimal & Percentage Representation
Dividing the numerator 37 by denominator 39 produces a repeating decimal (approximately 0.948718, or 94.8718%).
Working: 37 ÷ 39 = 0.948718 (94.8718%)

Key Values:
- Simplified Fraction: 37/39
- Mixed Number Form: 37/39
- Decimal Value: 0.948718
- Percentage: 94.8718%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-10-39-plus-9-13/
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10/39 + 9/13 = 37/39

Simplified Fraction

37/39

Mixed Number

Proper (37/39)

Decimal Value

0.948718

Percentage

94.8718%

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Step-by-Step Solution: 10/39 + 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 10/39 by 1, and multiply the numerator and denominator of 9/13 by 3 so both fractions share the common base 39.

10 × 1/39 × 1 = 10/39 and 9 × 3/13 × 3 = 27/39

Step 3

Add the Numerators

Now add the numerators (10 + 27 = 37) and keep the common denominator 39 unchanged.

10 + 27/39 = 37/39

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 37 and 39 is 1, confirming that 37/39 cannot be reduced further—it is already in its simplest irreducible form.

37/39

Step 5

Decimal & Percentage Representation

Dividing the numerator 37 by denominator 39 produces a repeating decimal (approximately 0.948718, or 94.8718%).

37 ÷ 39 = 0.948718 (94.8718%)

Visual Representation

The diagram below illustrates 10/39 plus 9/13 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`37/39`
Mixed Number Form	`37/39`
Decimal Form	`0.948718`
Percentage	`94.8718%`

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Frequently Asked Questions

What is 10/39 plus 9/13 as a fraction?

10/39 + 9/13 in simplest fraction form is 37/39.

What is 10/39 plus 9/13 as a decimal?

10/39 + 9/13 converted to a decimal is 0.948718.

What is 10/39 plus 9/13 as a percentage?

10/39 + 9/13 expressed as a percentage is 94.8718%.

Does 10/39 plus 9/13 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.948718...) because the denominator contains prime factors other than 2 and 5.