What is 15/47 plus 10/21? (Answer: 785/987)

Exact Answer

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Problem: What is 15/47 plus 10/21?
Formula / Expression: 15/47 + 10/21
Final Answer: 785/987
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 47 and 21 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 47 × 21 = 987.
Working: LCD(47, 21) = 987

Step 2: Convert to Equivalent Fractions with Common Denominator 987
Multiply the numerator and denominator of 15/47 by 21, and multiply the numerator and denominator of 10/21 by 47 so both fractions share the common base 987.
Working: 15 × 21/47 × 21 = 315/987 and 10 × 47/21 × 47 = 470/987

Step 3: Add the Numerators
Now add the numerators (315 + 470 = 785) and keep the common denominator 987 unchanged.
Working: 315 + 470/987 = 785/987

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 785 and 987 is 1, confirming that 785/987 cannot be reduced further—it is already in its simplest irreducible form.
Working: 785/987

Step 5: Decimal & Percentage Representation
Dividing the numerator 785 by denominator 987 produces a repeating decimal (approximately 0.795339, or 79.5339%).
Working: 785 ÷ 987 = 0.795339 (79.5339%)

Key Values:
- Simplified Fraction: 785/987
- Mixed Number Form: 785/987
- Decimal Value: 0.795339
- Percentage: 79.5339%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-15-47-plus-10-21/
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15/47 + 10/21 = 785/987

Simplified Fraction

785/987

Mixed Number

Proper (785/987)

Decimal Value

0.795339

Percentage

79.5339%

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Step-by-Step Solution: 15/47 + 10/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 47 and 21 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 47 × 21 = 987.

LCD(47, 21) = 987

Step 2

Convert to Equivalent Fractions with Common Denominator 987

Multiply the numerator and denominator of 15/47 by 21, and multiply the numerator and denominator of 10/21 by 47 so both fractions share the common base 987.

15 × 21/47 × 21 = 315/987 and 10 × 47/21 × 47 = 470/987

Step 3

Add the Numerators

Now add the numerators (315 + 470 = 785) and keep the common denominator 987 unchanged.

315 + 470/987 = 785/987

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 785 and 987 is 1, confirming that 785/987 cannot be reduced further—it is already in its simplest irreducible form.

785/987

Step 5

Decimal & Percentage Representation

Dividing the numerator 785 by denominator 987 produces a repeating decimal (approximately 0.795339, or 79.5339%).

785 ÷ 987 = 0.795339 (79.5339%)

Visual Representation

The diagram below illustrates 15/47 plus 10/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`785/987`
Mixed Number Form	`785/987`
Decimal Form	`0.795339`
Percentage	`79.5339%`

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Frequently Asked Questions

What is 15/47 plus 10/21 as a fraction?

15/47 + 10/21 in simplest fraction form is 785/987.

What is 15/47 plus 10/21 as a decimal?

15/47 + 10/21 converted to a decimal is 0.795339.

What is 15/47 plus 10/21 as a percentage?

15/47 + 10/21 expressed as a percentage is 79.5339%.

Does 15/47 plus 10/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.795339...) because the denominator contains prime factors other than 2 and 5.