What is 11/21 plus 9/17? (Answer: 376/357)

Exact Answer

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Problem: What is 11/21 plus 9/17?
Formula / Expression: 11/21 + 9/17
Final Answer: 1 19/357 (376/357)
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 21 and 17 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 21 × 17 = 357.
Working: LCD(21, 17) = 357

Step 2: Convert to Equivalent Fractions with Common Denominator 357
Multiply the numerator and denominator of 11/21 by 17, and multiply the numerator and denominator of 9/17 by 21 so both fractions share the common base 357.
Working: 11 × 17/21 × 17 = 187/357 and 9 × 21/17 × 21 = 189/357

Step 3: Add the Numerators
Now add the numerators (187 + 189 = 376) and keep the common denominator 357 unchanged.
Working: 187 + 189/357 = 376/357

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 376 and 357 is 1, confirming that 376/357 cannot be reduced further—it is already in its simplest irreducible form.
Working: 376/357

Step 5: Convert Improper Fraction to a Mixed Number
Since the numerator (376) is greater than the denominator (357), divide 376 by 357: it goes in 1 whole time(s) with a remainder of 19, giving the mixed number 1 19/357.
Working: 376/357 = 1 19/357

Step 6: Decimal & Percentage Representation
Dividing the numerator 376 by denominator 357 produces a repeating decimal (approximately 1.053221, or 105.3221%).
Working: 376 ÷ 357 = 1.053221 (105.3221%)

Key Values:
- Simplified Fraction: 376/357
- Mixed Number Form: 1 19/357
- Decimal Value: 1.053221
- Percentage: 105.3221%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-11-21-plus-9-17/
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11/21 + 9/17 = 376/357

Simplified Fraction

376/357

Mixed Number

1 19/357

Decimal Value

1.053221

Percentage

105.3221%

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Step-by-Step Solution: 11/21 + 9/17

Step 1

Find the Least Common Denominator (LCD)

The denominators 21 and 17 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 21 × 17 = 357.

LCD(21, 17) = 357

Step 2

Convert to Equivalent Fractions with Common Denominator 357

Multiply the numerator and denominator of 11/21 by 17, and multiply the numerator and denominator of 9/17 by 21 so both fractions share the common base 357.

11 × 17/21 × 17 = 187/357 and 9 × 21/17 × 21 = 189/357

Step 3

Add the Numerators

Now add the numerators (187 + 189 = 376) and keep the common denominator 357 unchanged.

187 + 189/357 = 376/357

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 376 and 357 is 1, confirming that 376/357 cannot be reduced further—it is already in its simplest irreducible form.

376/357

Step 5

Convert Improper Fraction to a Mixed Number

Since the numerator (376) is greater than the denominator (357), divide 376 by 357: it goes in 1 whole time(s) with a remainder of 19, giving the mixed number 1 19/357.

376/357 = 119/357

Step 6

Decimal & Percentage Representation

Dividing the numerator 376 by denominator 357 produces a repeating decimal (approximately 1.053221, or 105.3221%).

376 ÷ 357 = 1.053221 (105.3221%)

Visual Representation

The diagram below illustrates 11/21 plus 9/17 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`376/357`
Mixed Number Form	`1 19/357`
Decimal Form	`1.053221`
Percentage	`105.3221%`

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Frequently Asked Questions

What is 11/21 plus 9/17 as a fraction?

11/21 + 9/17 in simplest fraction form is 376/357 (or 1 19/357 as a mixed number).

What is 11/21 plus 9/17 as a decimal?

11/21 + 9/17 converted to a decimal is 1.053221.

What is 11/21 plus 9/17 as a percentage?

11/21 + 9/17 expressed as a percentage is 105.3221%.

How do you write 11/21 plus 9/17 as a mixed number?

Because the numerator is greater than the denominator, the improper fraction 376/357 can be written as the mixed number 1 19/357.

Does 11/21 plus 9/17 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 1.053221...) because the denominator contains prime factors other than 2 and 5.