What is 3/16 plus 12/21? (Answer: 85/112)

Exact Answer

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Problem: What is 3/16 plus 12/21?
Formula / Expression: 3/16 + 12/21
Final Answer: 85/112
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 16 and 21 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 16 × 21 = 336.
Working: LCD(16, 21) = 336

Step 2: Convert to Equivalent Fractions with Common Denominator 336
Multiply the numerator and denominator of 3/16 by 21, and multiply the numerator and denominator of 12/21 by 16 so both fractions share the common base 336.
Working: 3 × 21/16 × 21 = 63/336 and 12 × 16/21 × 16 = 192/336

Step 3: Add the Numerators
Now add the numerators (63 + 192 = 255) and keep the common denominator 336 unchanged.
Working: 63 + 192/336 = 255/336

Step 4: Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 255 and 336, which is 3. Divide both the numerator and denominator by 3.
Working: 255 ÷ 3/336 ÷ 3 = 85/112

Step 5: Decimal & Percentage Representation
Dividing the numerator 85 by denominator 112 produces a repeating decimal (approximately 0.758929, or 75.8929%).
Working: 85 ÷ 112 = 0.758929 (75.8929%)

Key Values:
- Simplified Fraction: 85/112
- Mixed Number Form: 85/112
- Decimal Value: 0.758929
- Percentage: 75.8929%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-3-16-plus-12-21/
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3/16 + 12/21 = 85/112

Simplified Fraction

85/112

Mixed Number

Proper (85/112)

Decimal Value

0.758929

Percentage

75.8929%

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Step-by-Step Solution: 3/16 + 12/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 16 and 21 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 16 × 21 = 336.

LCD(16, 21) = 336

Step 2

Convert to Equivalent Fractions with Common Denominator 336

Multiply the numerator and denominator of 3/16 by 21, and multiply the numerator and denominator of 12/21 by 16 so both fractions share the common base 336.

3 × 21/16 × 21 = 63/336 and 12 × 16/21 × 16 = 192/336

Step 3

Add the Numerators

Now add the numerators (63 + 192 = 255) and keep the common denominator 336 unchanged.

63 + 192/336 = 255/336

Step 4

Simplify the Fraction to Lowest Terms

Find the Greatest Common Divisor (GCD) of 255 and 336, which is 3. Divide both the numerator and denominator by 3.

255 ÷ 3/336 ÷ 3 = 85/112

Step 5

Decimal & Percentage Representation

Dividing the numerator 85 by denominator 112 produces a repeating decimal (approximately 0.758929, or 75.8929%).

85 ÷ 112 = 0.758929 (75.8929%)

Visual Representation

The diagram below illustrates 3/16 plus 12/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`85/112`
Mixed Number Form	`85/112`
Decimal Form	`0.758929`
Percentage	`75.8929%`

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Frequently Asked Questions

What is 3/16 plus 12/21 as a fraction?

3/16 + 12/21 in simplest fraction form is 85/112.

What is 3/16 plus 12/21 as a decimal?

3/16 + 12/21 converted to a decimal is 0.758929.

What is 3/16 plus 12/21 as a percentage?

3/16 + 12/21 expressed as a percentage is 75.8929%.

Does 3/16 plus 12/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.758929...) because the denominator contains prime factors other than 2 and 5.