What is 7/63 plus 4/21? (Answer: 19/63)

Exact Answer

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Problem: What is 7/63 plus 4/21?
Formula / Expression: 7/63 + 4/21
Final Answer: 19/63
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
Notice that 63 is an exact multiple of 21 (21 × 3 = 63). The Least Common Denominator (LCD) is simply 63, meaning we only need to scale one fraction.
Working: LCD(63, 21) = 63

Step 2: Convert to Equivalent Fractions with Common Denominator 63
Multiply the numerator and denominator of 7/63 by 1, and multiply the numerator and denominator of 4/21 by 3 so both fractions share the common base 63.
Working: 7 × 1/63 × 1 = 7/63 and 4 × 3/21 × 3 = 12/63

Step 3: Add the Numerators
Now add the numerators (7 + 12 = 19) and keep the common denominator 63 unchanged.
Working: 7 + 12/63 = 19/63

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 19 and 63 is 1, confirming that 19/63 cannot be reduced further—it is already in its simplest irreducible form.
Working: 19/63

Step 5: Decimal & Percentage Representation
Dividing the numerator 19 by denominator 63 produces a repeating decimal (approximately 0.301587, or 30.1587%).
Working: 19 ÷ 63 = 0.301587 (30.1587%)

Key Values:
- Simplified Fraction: 19/63
- Mixed Number Form: 19/63
- Decimal Value: 0.301587
- Percentage: 30.1587%

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Solved with FractionsCalc:
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7/63 + 4/21 = 19/63

Simplified Fraction

19/63

Mixed Number

Proper (19/63)

Decimal Value

0.301587

Percentage

30.1587%

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Step-by-Step Solution: 7/63 + 4/21

Step 1

Find the Least Common Denominator (LCD)

Notice that 63 is an exact multiple of 21 (21 × 3 = 63). The Least Common Denominator (LCD) is simply 63, meaning we only need to scale one fraction.

LCD(63, 21) = 63

Step 2

Convert to Equivalent Fractions with Common Denominator 63

Multiply the numerator and denominator of 7/63 by 1, and multiply the numerator and denominator of 4/21 by 3 so both fractions share the common base 63.

7 × 1/63 × 1 = 7/63 and 4 × 3/21 × 3 = 12/63

Step 3

Add the Numerators

Now add the numerators (7 + 12 = 19) and keep the common denominator 63 unchanged.

7 + 12/63 = 19/63

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 19 and 63 is 1, confirming that 19/63 cannot be reduced further—it is already in its simplest irreducible form.

19/63

Step 5

Decimal & Percentage Representation

Dividing the numerator 19 by denominator 63 produces a repeating decimal (approximately 0.301587, or 30.1587%).

19 ÷ 63 = 0.301587 (30.1587%)

Visual Representation

The diagram below illustrates 7/63 plus 4/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`19/63`
Mixed Number Form	`19/63`
Decimal Form	`0.301587`
Percentage	`30.1587%`

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Frequently Asked Questions

What is 7/63 plus 4/21 as a fraction?

7/63 + 4/21 in simplest fraction form is 19/63.

What is 7/63 plus 4/21 as a decimal?

7/63 + 4/21 converted to a decimal is 0.301587.

What is 7/63 plus 4/21 as a percentage?

7/63 + 4/21 expressed as a percentage is 30.1587%.

Does 7/63 plus 4/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.301587...) because the denominator contains prime factors other than 2 and 5.