What is 5/27 plus 15/21? (Answer: 170/189)

Exact Answer

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Problem: What is 5/27 plus 15/21?
Formula / Expression: 5/27 + 15/21
Final Answer: 170/189
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 27 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 189 (which is smaller than their product 27 × 21 = 567, keeping the calculation simpler).
Working: LCD(27, 21) = 189

Step 2: Convert to Equivalent Fractions with Common Denominator 189
Multiply the numerator and denominator of 5/27 by 7, and multiply the numerator and denominator of 15/21 by 9 so both fractions share the common base 189.
Working: 5 × 7/27 × 7 = 35/189 and 15 × 9/21 × 9 = 135/189

Step 3: Add the Numerators
Now add the numerators (35 + 135 = 170) and keep the common denominator 189 unchanged.
Working: 35 + 135/189 = 170/189

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 170 and 189 is 1, confirming that 170/189 cannot be reduced further—it is already in its simplest irreducible form.
Working: 170/189

Step 5: Decimal & Percentage Representation
Dividing the numerator 170 by denominator 189 produces a repeating decimal (approximately 0.899471, or 89.9471%).
Working: 170 ÷ 189 = 0.899471 (89.9471%)

Key Values:
- Simplified Fraction: 170/189
- Mixed Number Form: 170/189
- Decimal Value: 0.899471
- Percentage: 89.9471%

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Solved with FractionsCalc:
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5/27 + 15/21 = 170/189

Simplified Fraction

170/189

Mixed Number

Proper (170/189)

Decimal Value

0.899471

Percentage

89.9471%

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Step-by-Step Solution: 5/27 + 15/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 27 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 189 (which is smaller than their product 27 × 21 = 567, keeping the calculation simpler).

LCD(27, 21) = 189

Step 2

Convert to Equivalent Fractions with Common Denominator 189

Multiply the numerator and denominator of 5/27 by 7, and multiply the numerator and denominator of 15/21 by 9 so both fractions share the common base 189.

5 × 7/27 × 7 = 35/189 and 15 × 9/21 × 9 = 135/189

Step 3

Add the Numerators

Now add the numerators (35 + 135 = 170) and keep the common denominator 189 unchanged.

35 + 135/189 = 170/189

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 170 and 189 is 1, confirming that 170/189 cannot be reduced further—it is already in its simplest irreducible form.

170/189

Step 5

Decimal & Percentage Representation

Dividing the numerator 170 by denominator 189 produces a repeating decimal (approximately 0.899471, or 89.9471%).

170 ÷ 189 = 0.899471 (89.9471%)

Visual Representation

The diagram below illustrates 5/27 plus 15/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`170/189`
Mixed Number Form	`170/189`
Decimal Form	`0.899471`
Percentage	`89.9471%`

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Frequently Asked Questions

What is 5/27 plus 15/21 as a fraction?

5/27 + 15/21 in simplest fraction form is 170/189.

What is 5/27 plus 15/21 as a decimal?

5/27 + 15/21 converted to a decimal is 0.899471.

What is 5/27 plus 15/21 as a percentage?

5/27 + 15/21 expressed as a percentage is 89.9471%.

Does 5/27 plus 15/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.899471...) because the denominator contains prime factors other than 2 and 5.