What is 2/7 plus 5/15? (Answer: 13/21)

Exact Answer

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Problem: What is 2/7 plus 5/15?
Formula / Expression: 2/7 + 5/15
Final Answer: 13/21
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 7 and 15 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 7 × 15 = 105.
Working: LCD(7, 15) = 105

Step 2: Convert to Equivalent Fractions with Common Denominator 105
Multiply the numerator and denominator of 2/7 by 15, and multiply the numerator and denominator of 5/15 by 7 so both fractions share the common base 105.
Working: 2 × 15/7 × 15 = 30/105 and 5 × 7/15 × 7 = 35/105

Step 3: Add the Numerators
Now add the numerators (30 + 35 = 65) and keep the common denominator 105 unchanged.
Working: 30 + 35/105 = 65/105

Step 4: Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 65 and 105, which is 5. Divide both the numerator and denominator by 5.
Working: 65 ÷ 5/105 ÷ 5 = 13/21

Step 5: Decimal & Percentage Representation
Dividing the numerator 13 by denominator 21 produces a repeating decimal (approximately 0.619048, or 61.9048%).
Working: 13 ÷ 21 = 0.619048 (61.9048%)

Key Values:
- Simplified Fraction: 13/21
- Mixed Number Form: 13/21
- Decimal Value: 0.619048
- Percentage: 61.9048%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-2-7-plus-5-15/
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2/7 + 5/15 = 13/21

Simplified Fraction

13/21

Mixed Number

Proper (13/21)

Decimal Value

0.619048

Percentage

61.9048%

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Step-by-Step Solution: 2/7 + 5/15

Step 1

Find the Least Common Denominator (LCD)

The denominators 7 and 15 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 7 × 15 = 105.

LCD(7, 15) = 105

Step 2

Convert to Equivalent Fractions with Common Denominator 105

Multiply the numerator and denominator of 2/7 by 15, and multiply the numerator and denominator of 5/15 by 7 so both fractions share the common base 105.

2 × 15/7 × 15 = 30/105 and 5 × 7/15 × 7 = 35/105

Step 3

Add the Numerators

Now add the numerators (30 + 35 = 65) and keep the common denominator 105 unchanged.

30 + 35/105 = 65/105

Step 4

Simplify the Fraction to Lowest Terms

Find the Greatest Common Divisor (GCD) of 65 and 105, which is 5. Divide both the numerator and denominator by 5.

65 ÷ 5/105 ÷ 5 = 13/21

Step 5

Decimal & Percentage Representation

Dividing the numerator 13 by denominator 21 produces a repeating decimal (approximately 0.619048, or 61.9048%).

13 ÷ 21 = 0.619048 (61.9048%)

Visual Representation

The diagram below illustrates 2/7 plus 5/15 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`13/21`
Mixed Number Form	`13/21`
Decimal Form	`0.619048`
Percentage	`61.9048%`

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Frequently Asked Questions

What is 2/7 plus 5/15 as a fraction?

2/7 + 5/15 in simplest fraction form is 13/21.

What is 2/7 plus 5/15 as a decimal?

2/7 + 5/15 converted to a decimal is 0.619048.

What is 2/7 plus 5/15 as a percentage?

2/7 + 5/15 expressed as a percentage is 61.9048%.

Does 2/7 plus 5/15 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.619048...) because the denominator contains prime factors other than 2 and 5.