What is 20/54 plus 9/21? (Answer: 151/189)

Exact Answer

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Problem: What is 20/54 plus 9/21?
Formula / Expression: 20/54 + 9/21
Final Answer: 151/189
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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 20/54 by 7, and multiply the numerator and denominator of 9/21 by 18 so both fractions share the common base 378.
Working: 20 × 7/54 × 7 = 140/378 and 9 × 18/21 × 18 = 162/378

Step 3: Add the Numerators
Now add the numerators (140 + 162 = 302) and keep the common denominator 378 unchanged.
Working: 140 + 162/378 = 302/378

Step 4: Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 302 and 378, which is 2. Divide both the numerator and denominator by 2.
Working: 302 ÷ 2/378 ÷ 2 = 151/189

Step 5: Decimal & Percentage Representation
Dividing the numerator 151 by denominator 189 produces a repeating decimal (approximately 0.798942, or 79.8942%).
Working: 151 ÷ 189 = 0.798942 (79.8942%)

Key Values:
- Simplified Fraction: 151/189
- Mixed Number Form: 151/189
- Decimal Value: 0.798942
- Percentage: 79.8942%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-20-54-plus-9-21/
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20/54 + 9/21 = 151/189

Simplified Fraction

151/189

Mixed Number

Proper (151/189)

Decimal Value

0.798942

Percentage

79.8942%

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Step-by-Step Solution: 20/54 + 9/21

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 20/54 by 7, and multiply the numerator and denominator of 9/21 by 18 so both fractions share the common base 378.

20 × 7/54 × 7 = 140/378 and 9 × 18/21 × 18 = 162/378

Step 3

Add the Numerators

Now add the numerators (140 + 162 = 302) and keep the common denominator 378 unchanged.

140 + 162/378 = 302/378

Step 4

Simplify the Fraction to Lowest Terms

Find the Greatest Common Divisor (GCD) of 302 and 378, which is 2. Divide both the numerator and denominator by 2.

302 ÷ 2/378 ÷ 2 = 151/189

Step 5

Decimal & Percentage Representation

Dividing the numerator 151 by denominator 189 produces a repeating decimal (approximately 0.798942, or 79.8942%).

151 ÷ 189 = 0.798942 (79.8942%)

Visual Representation

The diagram below illustrates 20/54 plus 9/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`151/189`
Mixed Number Form	`151/189`
Decimal Form	`0.798942`
Percentage	`79.8942%`

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Frequently Asked Questions

What is 20/54 plus 9/21 as a fraction?

20/54 + 9/21 in simplest fraction form is 151/189.

What is 20/54 plus 9/21 as a decimal?

20/54 + 9/21 converted to a decimal is 0.798942.

What is 20/54 plus 9/21 as a percentage?

20/54 + 9/21 expressed as a percentage is 79.8942%.

Does 20/54 plus 9/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.798942...) because the denominator contains prime factors other than 2 and 5.