What is 12/58 plus 7/21? (Answer: 47/87)

Exact Answer

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Problem: What is 12/58 plus 7/21?
Formula / Expression: 12/58 + 7/21
Final Answer: 47/87
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 58 and 21 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 58 × 21 = 1218.
Working: LCD(58, 21) = 1218

Step 2: Convert to Equivalent Fractions with Common Denominator 1218
Multiply the numerator and denominator of 12/58 by 21, and multiply the numerator and denominator of 7/21 by 58 so both fractions share the common base 1218.
Working: 12 × 21/58 × 21 = 252/1218 and 7 × 58/21 × 58 = 406/1218

Step 3: Add the Numerators
Now add the numerators (252 + 406 = 658) and keep the common denominator 1218 unchanged.
Working: 252 + 406/1218 = 658/1218

Step 4: Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 658 and 1218, which is 14. Divide both the numerator and denominator by 14.
Working: 658 ÷ 14/1218 ÷ 14 = 47/87

Step 5: Decimal & Percentage Representation
Dividing the numerator 47 by denominator 87 produces a repeating decimal (approximately 0.54023, or 54.023%).
Working: 47 ÷ 87 = 0.54023 (54.023%)

Key Values:
- Simplified Fraction: 47/87
- Mixed Number Form: 47/87
- Decimal Value: 0.54023
- Percentage: 54.023%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-12-58-plus-7-21/
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12/58 + 7/21 = 47/87

Simplified Fraction

47/87

Mixed Number

Proper (47/87)

Decimal Value

0.54023

Percentage

54.023%

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Step-by-Step Solution: 12/58 + 7/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 58 and 21 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 58 × 21 = 1218.

LCD(58, 21) = 1218

Step 2

Convert to Equivalent Fractions with Common Denominator 1218

Multiply the numerator and denominator of 12/58 by 21, and multiply the numerator and denominator of 7/21 by 58 so both fractions share the common base 1218.

12 × 21/58 × 21 = 252/1218 and 7 × 58/21 × 58 = 406/1218

Step 3

Add the Numerators

Now add the numerators (252 + 406 = 658) and keep the common denominator 1218 unchanged.

252 + 406/1218 = 658/1218

Step 4

Simplify the Fraction to Lowest Terms

Find the Greatest Common Divisor (GCD) of 658 and 1218, which is 14. Divide both the numerator and denominator by 14.

658 ÷ 14/1218 ÷ 14 = 47/87

Step 5

Decimal & Percentage Representation

Dividing the numerator 47 by denominator 87 produces a repeating decimal (approximately 0.54023, or 54.023%).

47 ÷ 87 = 0.54023 (54.023%)

Visual Representation

The diagram below illustrates 12/58 plus 7/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`47/87`
Mixed Number Form	`47/87`
Decimal Form	`0.54023`
Percentage	`54.023%`

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Frequently Asked Questions

What is 12/58 plus 7/21 as a fraction?

12/58 + 7/21 in simplest fraction form is 47/87.

What is 12/58 plus 7/21 as a decimal?

12/58 + 7/21 converted to a decimal is 0.54023.

What is 12/58 plus 7/21 as a percentage?

12/58 + 7/21 expressed as a percentage is 54.023%.

Does 12/58 plus 7/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.54023...) because the denominator contains prime factors other than 2 and 5.