What is 15/49 plus 8/21? (Answer: 101/147)

Exact Answer

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Problem: What is 15/49 plus 8/21?
Formula / Expression: 15/49 + 8/21
Final Answer: 101/147
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 49 and 21 share a common factor (GCD = 7). Finding their Least Common Multiple gives an LCD of 147 (which is smaller than their product 49 × 21 = 1029, keeping the calculation simpler).
Working: LCD(49, 21) = 147

Step 2: Convert to Equivalent Fractions with Common Denominator 147
Multiply the numerator and denominator of 15/49 by 3, and multiply the numerator and denominator of 8/21 by 7 so both fractions share the common base 147.
Working: 15 × 3/49 × 3 = 45/147 and 8 × 7/21 × 7 = 56/147

Step 3: Add the Numerators
Now add the numerators (45 + 56 = 101) and keep the common denominator 147 unchanged.
Working: 45 + 56/147 = 101/147

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 101 and 147 is 1, confirming that 101/147 cannot be reduced further—it is already in its simplest irreducible form.
Working: 101/147

Step 5: Decimal & Percentage Representation
Dividing the numerator 101 by denominator 147 produces a repeating decimal (approximately 0.687075, or 68.7075%).
Working: 101 ÷ 147 = 0.687075 (68.7075%)

Key Values:
- Simplified Fraction: 101/147
- Mixed Number Form: 101/147
- Decimal Value: 0.687075
- Percentage: 68.7075%

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Solved with FractionsCalc:
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15/49 + 8/21 = 101/147

Simplified Fraction

101/147

Mixed Number

Proper (101/147)

Decimal Value

0.687075

Percentage

68.7075%

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Step-by-Step Solution: 15/49 + 8/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 49 and 21 share a common factor (GCD = 7). Finding their Least Common Multiple gives an LCD of 147 (which is smaller than their product 49 × 21 = 1029, keeping the calculation simpler).

LCD(49, 21) = 147

Step 2

Convert to Equivalent Fractions with Common Denominator 147

Multiply the numerator and denominator of 15/49 by 3, and multiply the numerator and denominator of 8/21 by 7 so both fractions share the common base 147.

15 × 3/49 × 3 = 45/147 and 8 × 7/21 × 7 = 56/147

Step 3

Add the Numerators

Now add the numerators (45 + 56 = 101) and keep the common denominator 147 unchanged.

45 + 56/147 = 101/147

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 101 and 147 is 1, confirming that 101/147 cannot be reduced further—it is already in its simplest irreducible form.

101/147

Step 5

Decimal & Percentage Representation

Dividing the numerator 101 by denominator 147 produces a repeating decimal (approximately 0.687075, or 68.7075%).

101 ÷ 147 = 0.687075 (68.7075%)

Visual Representation

The diagram below illustrates 15/49 plus 8/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`101/147`
Mixed Number Form	`101/147`
Decimal Form	`0.687075`
Percentage	`68.7075%`

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Frequently Asked Questions

What is 15/49 plus 8/21 as a fraction?

15/49 + 8/21 in simplest fraction form is 101/147.

What is 15/49 plus 8/21 as a decimal?

15/49 + 8/21 converted to a decimal is 0.687075.

What is 15/49 plus 8/21 as a percentage?

15/49 + 8/21 expressed as a percentage is 68.7075%.

Does 15/49 plus 8/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.687075...) because the denominator contains prime factors other than 2 and 5.