What is 15/33 plus 10/21? (Answer: 215/231)

Exact Answer

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Problem: What is 15/33 plus 10/21?
Formula / Expression: 15/33 + 10/21
Final Answer: 215/231
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 33 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 231 (which is smaller than their product 33 × 21 = 693, keeping the calculation simpler).
Working: LCD(33, 21) = 231

Step 2: Convert to Equivalent Fractions with Common Denominator 231
Multiply the numerator and denominator of 15/33 by 7, and multiply the numerator and denominator of 10/21 by 11 so both fractions share the common base 231.
Working: 15 × 7/33 × 7 = 105/231 and 10 × 11/21 × 11 = 110/231

Step 3: Add the Numerators
Now add the numerators (105 + 110 = 215) and keep the common denominator 231 unchanged.
Working: 105 + 110/231 = 215/231

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 215 and 231 is 1, confirming that 215/231 cannot be reduced further—it is already in its simplest irreducible form.
Working: 215/231

Step 5: Decimal & Percentage Representation
Dividing the numerator 215 by denominator 231 produces a repeating decimal (approximately 0.930736, or 93.0736%).
Working: 215 ÷ 231 = 0.930736 (93.0736%)

Key Values:
- Simplified Fraction: 215/231
- Mixed Number Form: 215/231
- Decimal Value: 0.930736
- Percentage: 93.0736%

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15/33 + 10/21 = 215/231

Simplified Fraction

215/231

Mixed Number

Proper (215/231)

Decimal Value

0.930736

Percentage

93.0736%

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Step-by-Step Solution: 15/33 + 10/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 33 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 231 (which is smaller than their product 33 × 21 = 693, keeping the calculation simpler).

LCD(33, 21) = 231

Step 2

Convert to Equivalent Fractions with Common Denominator 231

Multiply the numerator and denominator of 15/33 by 7, and multiply the numerator and denominator of 10/21 by 11 so both fractions share the common base 231.

15 × 7/33 × 7 = 105/231 and 10 × 11/21 × 11 = 110/231

Step 3

Add the Numerators

Now add the numerators (105 + 110 = 215) and keep the common denominator 231 unchanged.

105 + 110/231 = 215/231

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 215 and 231 is 1, confirming that 215/231 cannot be reduced further—it is already in its simplest irreducible form.

215/231

Step 5

Decimal & Percentage Representation

Dividing the numerator 215 by denominator 231 produces a repeating decimal (approximately 0.930736, or 93.0736%).

215 ÷ 231 = 0.930736 (93.0736%)

Visual Representation

The diagram below illustrates 15/33 plus 10/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`215/231`
Mixed Number Form	`215/231`
Decimal Form	`0.930736`
Percentage	`93.0736%`

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Frequently Asked Questions

What is 15/33 plus 10/21 as a fraction?

15/33 + 10/21 in simplest fraction form is 215/231.

What is 15/33 plus 10/21 as a decimal?

15/33 + 10/21 converted to a decimal is 0.930736.

What is 15/33 plus 10/21 as a percentage?

15/33 + 10/21 expressed as a percentage is 93.0736%.

Does 15/33 plus 10/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.930736...) because the denominator contains prime factors other than 2 and 5.