What is 4/27 plus 12/21? (Answer: 136/189)

Exact Answer

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Problem: What is 4/27 plus 12/21?
Formula / Expression: 4/27 + 12/21
Final Answer: 136/189
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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 4/27 by 7, and multiply the numerator and denominator of 12/21 by 9 so both fractions share the common base 189.
Working: 4 × 7/27 × 7 = 28/189 and 12 × 9/21 × 9 = 108/189

Step 3: Add the Numerators
Now add the numerators (28 + 108 = 136) and keep the common denominator 189 unchanged.
Working: 28 + 108/189 = 136/189

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 136 and 189 is 1, confirming that 136/189 cannot be reduced further—it is already in its simplest irreducible form.
Working: 136/189

Step 5: Decimal & Percentage Representation
Dividing the numerator 136 by denominator 189 produces a repeating decimal (approximately 0.719577, or 71.9577%).
Working: 136 ÷ 189 = 0.719577 (71.9577%)

Key Values:
- Simplified Fraction: 136/189
- Mixed Number Form: 136/189
- Decimal Value: 0.719577
- Percentage: 71.9577%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-4-27-plus-12-21/
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4/27 + 12/21 = 136/189

Simplified Fraction

136/189

Mixed Number

Proper (136/189)

Decimal Value

0.719577

Percentage

71.9577%

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Step-by-Step Solution: 4/27 + 12/21

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 4/27 by 7, and multiply the numerator and denominator of 12/21 by 9 so both fractions share the common base 189.

4 × 7/27 × 7 = 28/189 and 12 × 9/21 × 9 = 108/189

Step 3

Add the Numerators

Now add the numerators (28 + 108 = 136) and keep the common denominator 189 unchanged.

28 + 108/189 = 136/189

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 136 and 189 is 1, confirming that 136/189 cannot be reduced further—it is already in its simplest irreducible form.

136/189

Step 5

Decimal & Percentage Representation

Dividing the numerator 136 by denominator 189 produces a repeating decimal (approximately 0.719577, or 71.9577%).

136 ÷ 189 = 0.719577 (71.9577%)

Visual Representation

The diagram below illustrates 4/27 plus 12/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`136/189`
Mixed Number Form	`136/189`
Decimal Form	`0.719577`
Percentage	`71.9577%`

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Frequently Asked Questions

What is 4/27 plus 12/21 as a fraction?

4/27 + 12/21 in simplest fraction form is 136/189.

What is 4/27 plus 12/21 as a decimal?

4/27 + 12/21 converted to a decimal is 0.719577.

What is 4/27 plus 12/21 as a percentage?

4/27 + 12/21 expressed as a percentage is 71.9577%.

Does 4/27 plus 12/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.719577...) because the denominator contains prime factors other than 2 and 5.