What is 15/21 plus 16/22? (Answer: 111/77)

Exact Answer

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Problem: What is 15/21 plus 16/22?
Formula / Expression: 15/21 + 16/22
Final Answer: 1 34/77 (111/77)
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 21 and 22 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 21 × 22 = 462.
Working: LCD(21, 22) = 462

Step 2: Convert to Equivalent Fractions with Common Denominator 462
Multiply the numerator and denominator of 15/21 by 22, and multiply the numerator and denominator of 16/22 by 21 so both fractions share the common base 462.
Working: 15 × 22/21 × 22 = 330/462 and 16 × 21/22 × 21 = 336/462

Step 3: Add the Numerators
Now add the numerators (330 + 336 = 666) and keep the common denominator 462 unchanged.
Working: 330 + 336/462 = 666/462

Step 4: Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 666 and 462, which is 6. Divide both the numerator and denominator by 6.
Working: 666 ÷ 6/462 ÷ 6 = 111/77

Step 5: Convert Improper Fraction to a Mixed Number
Since the numerator (111) is greater than the denominator (77), divide 111 by 77: it goes in 1 whole time(s) with a remainder of 34, giving the mixed number 1 34/77.
Working: 111/77 = 1 34/77

Step 6: Decimal & Percentage Representation
Dividing the numerator 111 by denominator 77 produces a repeating decimal (approximately 1.441558, or 144.1558%).
Working: 111 ÷ 77 = 1.441558 (144.1558%)

Key Values:
- Simplified Fraction: 111/77
- Mixed Number Form: 1 34/77
- Decimal Value: 1.441558
- Percentage: 144.1558%

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Solved with FractionsCalc:
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15/21 + 16/22 = 111/77

Simplified Fraction

111/77

Mixed Number

1 34/77

Decimal Value

1.441558

Percentage

144.1558%

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Step-by-Step Solution: 15/21 + 16/22

Step 1

Find the Least Common Denominator (LCD)

The denominators 21 and 22 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 21 × 22 = 462.

LCD(21, 22) = 462

Step 2

Convert to Equivalent Fractions with Common Denominator 462

Multiply the numerator and denominator of 15/21 by 22, and multiply the numerator and denominator of 16/22 by 21 so both fractions share the common base 462.

15 × 22/21 × 22 = 330/462 and 16 × 21/22 × 21 = 336/462

Step 3

Add the Numerators

Now add the numerators (330 + 336 = 666) and keep the common denominator 462 unchanged.

330 + 336/462 = 666/462

Step 4

Simplify the Fraction to Lowest Terms

Find the Greatest Common Divisor (GCD) of 666 and 462, which is 6. Divide both the numerator and denominator by 6.

666 ÷ 6/462 ÷ 6 = 111/77

Step 5

Convert Improper Fraction to a Mixed Number

Since the numerator (111) is greater than the denominator (77), divide 111 by 77: it goes in 1 whole time(s) with a remainder of 34, giving the mixed number 1 34/77.

111/77 = 134/77

Step 6

Decimal & Percentage Representation

Dividing the numerator 111 by denominator 77 produces a repeating decimal (approximately 1.441558, or 144.1558%).

111 ÷ 77 = 1.441558 (144.1558%)

Visual Representation

The diagram below illustrates 15/21 plus 16/22 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`111/77`
Mixed Number Form	`1 34/77`
Decimal Form	`1.441558`
Percentage	`144.1558%`

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Frequently Asked Questions

What is 15/21 plus 16/22 as a fraction?

15/21 + 16/22 in simplest fraction form is 111/77 (or 1 34/77 as a mixed number).

What is 15/21 plus 16/22 as a decimal?

15/21 + 16/22 converted to a decimal is 1.441558.

What is 15/21 plus 16/22 as a percentage?

15/21 + 16/22 expressed as a percentage is 144.1558%.

How do you write 15/21 plus 16/22 as a mixed number?

Because the numerator is greater than the denominator, the improper fraction 111/77 can be written as the mixed number 1 34/77.

Does 15/21 plus 16/22 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 1.441558...) because the denominator contains prime factors other than 2 and 5.