What is 10/57 plus 5/21? (Answer: 55/133)

Exact Answer

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Problem: What is 10/57 plus 5/21?
Formula / Expression: 10/57 + 5/21
Final Answer: 55/133
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 57 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 399 (which is smaller than their product 57 × 21 = 1197, keeping the calculation simpler).
Working: LCD(57, 21) = 399

Step 2: Convert to Equivalent Fractions with Common Denominator 399
Multiply the numerator and denominator of 10/57 by 7, and multiply the numerator and denominator of 5/21 by 19 so both fractions share the common base 399.
Working: 10 × 7/57 × 7 = 70/399 and 5 × 19/21 × 19 = 95/399

Step 3: Add the Numerators
Now add the numerators (70 + 95 = 165) and keep the common denominator 399 unchanged.
Working: 70 + 95/399 = 165/399

Step 4: Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 165 and 399, which is 3. Divide both the numerator and denominator by 3.
Working: 165 ÷ 3/399 ÷ 3 = 55/133

Step 5: Decimal & Percentage Representation
Dividing the numerator 55 by denominator 133 produces a repeating decimal (approximately 0.413534, or 41.3534%).
Working: 55 ÷ 133 = 0.413534 (41.3534%)

Key Values:
- Simplified Fraction: 55/133
- Mixed Number Form: 55/133
- Decimal Value: 0.413534
- Percentage: 41.3534%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-10-57-plus-5-21/
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10/57 + 5/21 = 55/133

Simplified Fraction

55/133

Mixed Number

Proper (55/133)

Decimal Value

0.413534

Percentage

41.3534%

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Step-by-Step Solution: 10/57 + 5/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 57 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 399 (which is smaller than their product 57 × 21 = 1197, keeping the calculation simpler).

LCD(57, 21) = 399

Step 2

Convert to Equivalent Fractions with Common Denominator 399

Multiply the numerator and denominator of 10/57 by 7, and multiply the numerator and denominator of 5/21 by 19 so both fractions share the common base 399.

10 × 7/57 × 7 = 70/399 and 5 × 19/21 × 19 = 95/399

Step 3

Add the Numerators

Now add the numerators (70 + 95 = 165) and keep the common denominator 399 unchanged.

70 + 95/399 = 165/399

Step 4

Simplify the Fraction to Lowest Terms

Find the Greatest Common Divisor (GCD) of 165 and 399, which is 3. Divide both the numerator and denominator by 3.

165 ÷ 3/399 ÷ 3 = 55/133

Step 5

Decimal & Percentage Representation

Dividing the numerator 55 by denominator 133 produces a repeating decimal (approximately 0.413534, or 41.3534%).

55 ÷ 133 = 0.413534 (41.3534%)

Visual Representation

The diagram below illustrates 10/57 plus 5/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`55/133`
Mixed Number Form	`55/133`
Decimal Form	`0.413534`
Percentage	`41.3534%`

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Frequently Asked Questions

What is 10/57 plus 5/21 as a fraction?

10/57 + 5/21 in simplest fraction form is 55/133.

What is 10/57 plus 5/21 as a decimal?

10/57 + 5/21 converted to a decimal is 0.413534.

What is 10/57 plus 5/21 as a percentage?

10/57 + 5/21 expressed as a percentage is 41.3534%.

Does 10/57 plus 5/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.413534...) because the denominator contains prime factors other than 2 and 5.