What is 9/21 plus 2/4? (Answer: 13/14)

Exact Answer

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Problem: What is 9/21 plus 2/4?
Formula / Expression: 9/21 + 2/4
Final Answer: 13/14
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 21 and 4 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 21 × 4 = 84.
Working: LCD(21, 4) = 84

Step 2: Convert to Equivalent Fractions with Common Denominator 84
Multiply the numerator and denominator of 9/21 by 4, and multiply the numerator and denominator of 2/4 by 21 so both fractions share the common base 84.
Working: 9 × 4/21 × 4 = 36/84 and 2 × 21/4 × 21 = 42/84

Step 3: Add the Numerators
Now add the numerators (36 + 42 = 78) and keep the common denominator 84 unchanged.
Working: 36 + 42/84 = 78/84

Step 4: Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 78 and 84, which is 6. Divide both the numerator and denominator by 6.
Working: 78 ÷ 6/84 ÷ 6 = 13/14

Step 5: Decimal & Percentage Representation
Dividing the numerator 13 by denominator 14 produces a repeating decimal (approximately 0.928571, or 92.8571%).
Working: 13 ÷ 14 = 0.928571 (92.8571%)

Key Values:
- Simplified Fraction: 13/14
- Mixed Number Form: 13/14
- Decimal Value: 0.928571
- Percentage: 92.8571%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-9-21-plus-2-4/
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9/21 + 2/4 = 13/14

Simplified Fraction

13/14

Mixed Number

Proper (13/14)

Decimal Value

0.928571

Percentage

92.8571%

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Step-by-Step Solution: 9/21 + 2/4

Step 1

Find the Least Common Denominator (LCD)

The denominators 21 and 4 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 21 × 4 = 84.

LCD(21, 4) = 84

Step 2

Convert to Equivalent Fractions with Common Denominator 84

Multiply the numerator and denominator of 9/21 by 4, and multiply the numerator and denominator of 2/4 by 21 so both fractions share the common base 84.

9 × 4/21 × 4 = 36/84 and 2 × 21/4 × 21 = 42/84

Step 3

Add the Numerators

Now add the numerators (36 + 42 = 78) and keep the common denominator 84 unchanged.

36 + 42/84 = 78/84

Step 4

Simplify the Fraction to Lowest Terms

Find the Greatest Common Divisor (GCD) of 78 and 84, which is 6. Divide both the numerator and denominator by 6.

78 ÷ 6/84 ÷ 6 = 13/14

Step 5

Decimal & Percentage Representation

Dividing the numerator 13 by denominator 14 produces a repeating decimal (approximately 0.928571, or 92.8571%).

13 ÷ 14 = 0.928571 (92.8571%)

Visual Representation

The diagram below illustrates 9/21 plus 2/4 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`13/14`
Mixed Number Form	`13/14`
Decimal Form	`0.928571`
Percentage	`92.8571%`

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Frequently Asked Questions

What is 9/21 plus 2/4 as a fraction?

9/21 + 2/4 in simplest fraction form is 13/14.

What is 9/21 plus 2/4 as a decimal?

9/21 + 2/4 converted to a decimal is 0.928571.

What is 9/21 plus 2/4 as a percentage?

9/21 + 2/4 expressed as a percentage is 92.8571%.

Does 9/21 plus 2/4 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.928571...) because the denominator contains prime factors other than 2 and 5.