What is 10/25 plus 9/21? (Answer: 29/35)

Exact Answer

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Problem: What is 10/25 plus 9/21?
Formula / Expression: 10/25 + 9/21
Final Answer: 29/35
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 25 and 21 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 25 × 21 = 525.
Working: LCD(25, 21) = 525

Step 2: Convert to Equivalent Fractions with Common Denominator 525
Multiply the numerator and denominator of 10/25 by 21, and multiply the numerator and denominator of 9/21 by 25 so both fractions share the common base 525.
Working: 10 × 21/25 × 21 = 210/525 and 9 × 25/21 × 25 = 225/525

Step 3: Add the Numerators
Now add the numerators (210 + 225 = 435) and keep the common denominator 525 unchanged.
Working: 210 + 225/525 = 435/525

Step 4: Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 435 and 525, which is 15. Divide both the numerator and denominator by 15.
Working: 435 ÷ 15/525 ÷ 15 = 29/35

Step 5: Decimal & Percentage Representation
Dividing the numerator 29 by denominator 35 produces a repeating decimal (approximately 0.828571, or 82.8571%).
Working: 29 ÷ 35 = 0.828571 (82.8571%)

Key Values:
- Simplified Fraction: 29/35
- Mixed Number Form: 29/35
- Decimal Value: 0.828571
- Percentage: 82.8571%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-10-25-plus-9-21/
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10/25 + 9/21 = 29/35

Simplified Fraction

29/35

Mixed Number

Proper (29/35)

Decimal Value

0.828571

Percentage

82.8571%

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Step-by-Step Solution: 10/25 + 9/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 25 and 21 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 25 × 21 = 525.

LCD(25, 21) = 525

Step 2

Convert to Equivalent Fractions with Common Denominator 525

Multiply the numerator and denominator of 10/25 by 21, and multiply the numerator and denominator of 9/21 by 25 so both fractions share the common base 525.

10 × 21/25 × 21 = 210/525 and 9 × 25/21 × 25 = 225/525

Step 3

Add the Numerators

Now add the numerators (210 + 225 = 435) and keep the common denominator 525 unchanged.

210 + 225/525 = 435/525

Step 4

Simplify the Fraction to Lowest Terms

Find the Greatest Common Divisor (GCD) of 435 and 525, which is 15. Divide both the numerator and denominator by 15.

435 ÷ 15/525 ÷ 15 = 29/35

Step 5

Decimal & Percentage Representation

Dividing the numerator 29 by denominator 35 produces a repeating decimal (approximately 0.828571, or 82.8571%).

29 ÷ 35 = 0.828571 (82.8571%)

Visual Representation

The diagram below illustrates 10/25 plus 9/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`29/35`
Mixed Number Form	`29/35`
Decimal Form	`0.828571`
Percentage	`82.8571%`

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Frequently Asked Questions

What is 10/25 plus 9/21 as a fraction?

10/25 + 9/21 in simplest fraction form is 29/35.

What is 10/25 plus 9/21 as a decimal?

10/25 + 9/21 converted to a decimal is 0.828571.

What is 10/25 plus 9/21 as a percentage?

10/25 + 9/21 expressed as a percentage is 82.8571%.

Does 10/25 plus 9/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.828571...) because the denominator contains prime factors other than 2 and 5.