What is 11/54 plus 8/21? (Answer: 221/378)

Exact Answer

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Problem: What is 11/54 plus 8/21?
Formula / Expression: 11/54 + 8/21
Final Answer: 221/378
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 54 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 378 (which is smaller than their product 54 × 21 = 1134, keeping the calculation simpler).
Working: LCD(54, 21) = 378

Step 2: Convert to Equivalent Fractions with Common Denominator 378
Multiply the numerator and denominator of 11/54 by 7, and multiply the numerator and denominator of 8/21 by 18 so both fractions share the common base 378.
Working: 11 × 7/54 × 7 = 77/378 and 8 × 18/21 × 18 = 144/378

Step 3: Add the Numerators
Now add the numerators (77 + 144 = 221) and keep the common denominator 378 unchanged.
Working: 77 + 144/378 = 221/378

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 221 and 378 is 1, confirming that 221/378 cannot be reduced further—it is already in its simplest irreducible form.
Working: 221/378

Step 5: Decimal & Percentage Representation
Dividing the numerator 221 by denominator 378 produces a repeating decimal (approximately 0.584656, or 58.4656%).
Working: 221 ÷ 378 = 0.584656 (58.4656%)

Key Values:
- Simplified Fraction: 221/378
- Mixed Number Form: 221/378
- Decimal Value: 0.584656
- Percentage: 58.4656%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-11-54-plus-8-21/
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11/54 + 8/21 = 221/378

Simplified Fraction

221/378

Mixed Number

Proper (221/378)

Decimal Value

0.584656

Percentage

58.4656%

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Step-by-Step Solution: 11/54 + 8/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 54 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 378 (which is smaller than their product 54 × 21 = 1134, keeping the calculation simpler).

LCD(54, 21) = 378

Step 2

Convert to Equivalent Fractions with Common Denominator 378

Multiply the numerator and denominator of 11/54 by 7, and multiply the numerator and denominator of 8/21 by 18 so both fractions share the common base 378.

11 × 7/54 × 7 = 77/378 and 8 × 18/21 × 18 = 144/378

Step 3

Add the Numerators

Now add the numerators (77 + 144 = 221) and keep the common denominator 378 unchanged.

77 + 144/378 = 221/378

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 221 and 378 is 1, confirming that 221/378 cannot be reduced further—it is already in its simplest irreducible form.

221/378

Step 5

Decimal & Percentage Representation

Dividing the numerator 221 by denominator 378 produces a repeating decimal (approximately 0.584656, or 58.4656%).

221 ÷ 378 = 0.584656 (58.4656%)

Visual Representation

The diagram below illustrates 11/54 plus 8/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`221/378`
Mixed Number Form	`221/378`
Decimal Form	`0.584656`
Percentage	`58.4656%`

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Frequently Asked Questions

What is 11/54 plus 8/21 as a fraction?

11/54 + 8/21 in simplest fraction form is 221/378.

What is 11/54 plus 8/21 as a decimal?

11/54 + 8/21 converted to a decimal is 0.584656.

What is 11/54 plus 8/21 as a percentage?

11/54 + 8/21 expressed as a percentage is 58.4656%.

Does 11/54 plus 8/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.584656...) because the denominator contains prime factors other than 2 and 5.