What is 11/51 plus 7/21? (Answer: 28/51)

Exact Answer

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Problem: What is 11/51 plus 7/21?
Formula / Expression: 11/51 + 7/21
Final Answer: 28/51
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 51 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 357 (which is smaller than their product 51 × 21 = 1071, keeping the calculation simpler).
Working: LCD(51, 21) = 357

Step 2: Convert to Equivalent Fractions with Common Denominator 357
Multiply the numerator and denominator of 11/51 by 7, and multiply the numerator and denominator of 7/21 by 17 so both fractions share the common base 357.
Working: 11 × 7/51 × 7 = 77/357 and 7 × 17/21 × 17 = 119/357

Step 3: Add the Numerators
Now add the numerators (77 + 119 = 196) and keep the common denominator 357 unchanged.
Working: 77 + 119/357 = 196/357

Step 4: Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 196 and 357, which is 7. Divide both the numerator and denominator by 7.
Working: 196 ÷ 7/357 ÷ 7 = 28/51

Step 5: Decimal & Percentage Representation
Dividing the numerator 28 by denominator 51 produces a repeating decimal (approximately 0.54902, or 54.902%).
Working: 28 ÷ 51 = 0.54902 (54.902%)

Key Values:
- Simplified Fraction: 28/51
- Mixed Number Form: 28/51
- Decimal Value: 0.54902
- Percentage: 54.902%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-11-51-plus-7-21/
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11/51 + 7/21 = 28/51

Simplified Fraction

28/51

Mixed Number

Proper (28/51)

Decimal Value

0.54902

Percentage

54.902%

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Step-by-Step Solution: 11/51 + 7/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 51 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 357 (which is smaller than their product 51 × 21 = 1071, keeping the calculation simpler).

LCD(51, 21) = 357

Step 2

Convert to Equivalent Fractions with Common Denominator 357

Multiply the numerator and denominator of 11/51 by 7, and multiply the numerator and denominator of 7/21 by 17 so both fractions share the common base 357.

11 × 7/51 × 7 = 77/357 and 7 × 17/21 × 17 = 119/357

Step 3

Add the Numerators

Now add the numerators (77 + 119 = 196) and keep the common denominator 357 unchanged.

77 + 119/357 = 196/357

Step 4

Simplify the Fraction to Lowest Terms

Find the Greatest Common Divisor (GCD) of 196 and 357, which is 7. Divide both the numerator and denominator by 7.

196 ÷ 7/357 ÷ 7 = 28/51

Step 5

Decimal & Percentage Representation

Dividing the numerator 28 by denominator 51 produces a repeating decimal (approximately 0.54902, or 54.902%).

28 ÷ 51 = 0.54902 (54.902%)

Visual Representation

The diagram below illustrates 11/51 plus 7/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`28/51`
Mixed Number Form	`28/51`
Decimal Form	`0.54902`
Percentage	`54.902%`

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Frequently Asked Questions

What is 11/51 plus 7/21 as a fraction?

11/51 + 7/21 in simplest fraction form is 28/51.

What is 11/51 plus 7/21 as a decimal?

11/51 + 7/21 converted to a decimal is 0.54902.

What is 11/51 plus 7/21 as a percentage?

11/51 + 7/21 expressed as a percentage is 54.902%.

Does 11/51 plus 7/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.54902...) because the denominator contains prime factors other than 2 and 5.