What is 3/10 plus 9/13? (Answer: 129/130)

Exact Answer

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Problem: What is 3/10 plus 9/13?
Formula / Expression: 3/10 + 9/13
Final Answer: 129/130
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 10 and 13 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 10 × 13 = 130.
Working: LCD(10, 13) = 130

Step 2: Convert to Equivalent Fractions with Common Denominator 130
Multiply the numerator and denominator of 3/10 by 13, and multiply the numerator and denominator of 9/13 by 10 so both fractions share the common base 130.
Working: 3 × 13/10 × 13 = 39/130 and 9 × 10/13 × 10 = 90/130

Step 3: Add the Numerators
Now add the numerators (39 + 90 = 129) and keep the common denominator 130 unchanged.
Working: 39 + 90/130 = 129/130

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 129 and 130 is 1, confirming that 129/130 cannot be reduced further—it is already in its simplest irreducible form.
Working: 129/130

Step 5: Decimal & Percentage Representation
Dividing the numerator 129 by denominator 130 produces a repeating decimal (approximately 0.992308, or 99.2308%).
Working: 129 ÷ 130 = 0.992308 (99.2308%)

Key Values:
- Simplified Fraction: 129/130
- Mixed Number Form: 129/130
- Decimal Value: 0.992308
- Percentage: 99.2308%

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Solved with FractionsCalc:
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3/10 + 9/13 = 129/130

Simplified Fraction

129/130

Mixed Number

Proper (129/130)

Decimal Value

0.992308

Percentage

99.2308%

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Step-by-Step Solution: 3/10 + 9/13

Step 1

Find the Least Common Denominator (LCD)

The denominators 10 and 13 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 10 × 13 = 130.

LCD(10, 13) = 130

Step 2

Convert to Equivalent Fractions with Common Denominator 130

Multiply the numerator and denominator of 3/10 by 13, and multiply the numerator and denominator of 9/13 by 10 so both fractions share the common base 130.

3 × 13/10 × 13 = 39/130 and 9 × 10/13 × 10 = 90/130

Step 3

Add the Numerators

Now add the numerators (39 + 90 = 129) and keep the common denominator 130 unchanged.

39 + 90/130 = 129/130

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 129 and 130 is 1, confirming that 129/130 cannot be reduced further—it is already in its simplest irreducible form.

129/130

Step 5

Decimal & Percentage Representation

Dividing the numerator 129 by denominator 130 produces a repeating decimal (approximately 0.992308, or 99.2308%).

129 ÷ 130 = 0.992308 (99.2308%)

Visual Representation

The diagram below illustrates 3/10 plus 9/13 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`129/130`
Mixed Number Form	`129/130`
Decimal Form	`0.992308`
Percentage	`99.2308%`

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Frequently Asked Questions

What is 3/10 plus 9/13 as a fraction?

3/10 + 9/13 in simplest fraction form is 129/130.

What is 3/10 plus 9/13 as a decimal?

3/10 + 9/13 converted to a decimal is 0.992308.

What is 3/10 plus 9/13 as a percentage?

3/10 + 9/13 expressed as a percentage is 99.2308%.

Does 3/10 plus 9/13 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.992308...) because the denominator contains prime factors other than 2 and 5.