What is 10/49 plus 7/21? (Answer: 79/147)

Exact Answer

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Problem: What is 10/49 plus 7/21?
Formula / Expression: 10/49 + 7/21
Final Answer: 79/147
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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 10/49 by 3, and multiply the numerator and denominator of 7/21 by 7 so both fractions share the common base 147.
Working: 10 × 3/49 × 3 = 30/147 and 7 × 7/21 × 7 = 49/147

Step 3: Add the Numerators
Now add the numerators (30 + 49 = 79) and keep the common denominator 147 unchanged.
Working: 30 + 49/147 = 79/147

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 79 and 147 is 1, confirming that 79/147 cannot be reduced further—it is already in its simplest irreducible form.
Working: 79/147

Step 5: Decimal & Percentage Representation
Dividing the numerator 79 by denominator 147 produces a repeating decimal (approximately 0.537415, or 53.7415%).
Working: 79 ÷ 147 = 0.537415 (53.7415%)

Key Values:
- Simplified Fraction: 79/147
- Mixed Number Form: 79/147
- Decimal Value: 0.537415
- Percentage: 53.7415%

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10/49 + 7/21 = 79/147

Simplified Fraction

79/147

Mixed Number

Proper (79/147)

Decimal Value

0.537415

Percentage

53.7415%

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Step-by-Step Solution: 10/49 + 7/21

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 10/49 by 3, and multiply the numerator and denominator of 7/21 by 7 so both fractions share the common base 147.

10 × 3/49 × 3 = 30/147 and 7 × 7/21 × 7 = 49/147

Step 3

Add the Numerators

Now add the numerators (30 + 49 = 79) and keep the common denominator 147 unchanged.

30 + 49/147 = 79/147

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 79 and 147 is 1, confirming that 79/147 cannot be reduced further—it is already in its simplest irreducible form.

79/147

Step 5

Decimal & Percentage Representation

Dividing the numerator 79 by denominator 147 produces a repeating decimal (approximately 0.537415, or 53.7415%).

79 ÷ 147 = 0.537415 (53.7415%)

Visual Representation

The diagram below illustrates 10/49 plus 7/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`79/147`
Mixed Number Form	`79/147`
Decimal Form	`0.537415`
Percentage	`53.7415%`

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Frequently Asked Questions

What is 10/49 plus 7/21 as a fraction?

10/49 + 7/21 in simplest fraction form is 79/147.

What is 10/49 plus 7/21 as a decimal?

10/49 + 7/21 converted to a decimal is 0.537415.

What is 10/49 plus 7/21 as a percentage?

10/49 + 7/21 expressed as a percentage is 53.7415%.

Does 10/49 plus 7/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.537415...) because the denominator contains prime factors other than 2 and 5.