What is 1/54 plus 8/21? (Answer: 151/378)

Exact Answer

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Problem: What is 1/54 plus 8/21?
Formula / Expression: 1/54 + 8/21
Final Answer: 151/378
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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 1/54 by 7, and multiply the numerator and denominator of 8/21 by 18 so both fractions share the common base 378.
Working: 1 × 7/54 × 7 = 7/378 and 8 × 18/21 × 18 = 144/378

Step 3: Add the Numerators
Now add the numerators (7 + 144 = 151) and keep the common denominator 378 unchanged.
Working: 7 + 144/378 = 151/378

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 151 and 378 is 1, confirming that 151/378 cannot be reduced further—it is already in its simplest irreducible form.
Working: 151/378

Step 5: Decimal & Percentage Representation
Dividing the numerator 151 by denominator 378 produces a repeating decimal (approximately 0.399471, or 39.9471%).
Working: 151 ÷ 378 = 0.399471 (39.9471%)

Key Values:
- Simplified Fraction: 151/378
- Mixed Number Form: 151/378
- Decimal Value: 0.399471
- Percentage: 39.9471%

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Solved with FractionsCalc:
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1/54 + 8/21 = 151/378

Simplified Fraction

151/378

Mixed Number

Proper (151/378)

Decimal Value

0.399471

Percentage

39.9471%

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Step-by-Step Solution: 1/54 + 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 1/54 by 7, and multiply the numerator and denominator of 8/21 by 18 so both fractions share the common base 378.

1 × 7/54 × 7 = 7/378 and 8 × 18/21 × 18 = 144/378

Step 3

Add the Numerators

Now add the numerators (7 + 144 = 151) and keep the common denominator 378 unchanged.

7 + 144/378 = 151/378

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 151 and 378 is 1, confirming that 151/378 cannot be reduced further—it is already in its simplest irreducible form.

151/378

Step 5

Decimal & Percentage Representation

Dividing the numerator 151 by denominator 378 produces a repeating decimal (approximately 0.399471, or 39.9471%).

151 ÷ 378 = 0.399471 (39.9471%)

Visual Representation

The diagram below illustrates 1/54 plus 8/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`151/378`
Mixed Number Form	`151/378`
Decimal Form	`0.399471`
Percentage	`39.9471%`

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Frequently Asked Questions

What is 1/54 plus 8/21 as a fraction?

1/54 + 8/21 in simplest fraction form is 151/378.

What is 1/54 plus 8/21 as a decimal?

1/54 + 8/21 converted to a decimal is 0.399471.

What is 1/54 plus 8/21 as a percentage?

1/54 + 8/21 expressed as a percentage is 39.9471%.

Does 1/54 plus 8/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.399471...) because the denominator contains prime factors other than 2 and 5.