What is 4/28 plus 4/21? (Answer: 1/3)

Exact Answer

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Problem: What is 4/28 plus 4/21?
Formula / Expression: 4/28 + 4/21
Final Answer: 1/3
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 28 and 21 share a common factor (GCD = 7). Finding their Least Common Multiple gives an LCD of 84 (which is smaller than their product 28 × 21 = 588, keeping the calculation simpler).
Working: LCD(28, 21) = 84

Step 2: Convert to Equivalent Fractions with Common Denominator 84
Multiply the numerator and denominator of 4/28 by 3, and multiply the numerator and denominator of 4/21 by 4 so both fractions share the common base 84.
Working: 4 × 3/28 × 3 = 12/84 and 4 × 4/21 × 4 = 16/84

Step 3: Add the Numerators
Now add the numerators (12 + 16 = 28) and keep the common denominator 84 unchanged.
Working: 12 + 16/84 = 28/84

Step 4: Simplify the Fraction to Lowest Terms
Find the Greatest Common Divisor (GCD) of 28 and 84, which is 28. Divide both the numerator and denominator by 28.
Working: 28 ÷ 28/84 ÷ 28 = 1/3

Step 5: Decimal & Percentage Representation
Dividing the numerator 1 by denominator 3 produces a repeating decimal (approximately 0.333333, or 33.3333%).
Working: 1 ÷ 3 = 0.333333 (33.3333%)

Key Values:
- Simplified Fraction: 1/3
- Mixed Number Form: 1/3
- Decimal Value: 0.333333
- Percentage: 33.3333%

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Solved with FractionsCalc:
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4/28 + 4/21 = 1/3

Simplified Fraction

1/3

Mixed Number

Proper (1/3)

Decimal Value

0.333333

Percentage

33.3333%

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Step-by-Step Solution: 4/28 + 4/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 28 and 21 share a common factor (GCD = 7). Finding their Least Common Multiple gives an LCD of 84 (which is smaller than their product 28 × 21 = 588, keeping the calculation simpler).

LCD(28, 21) = 84

Step 2

Convert to Equivalent Fractions with Common Denominator 84

Multiply the numerator and denominator of 4/28 by 3, and multiply the numerator and denominator of 4/21 by 4 so both fractions share the common base 84.

4 × 3/28 × 3 = 12/84 and 4 × 4/21 × 4 = 16/84

Step 3

Add the Numerators

Now add the numerators (12 + 16 = 28) and keep the common denominator 84 unchanged.

12 + 16/84 = 28/84

Step 4

Simplify the Fraction to Lowest Terms

Find the Greatest Common Divisor (GCD) of 28 and 84, which is 28. Divide both the numerator and denominator by 28.

28 ÷ 28/84 ÷ 28 = 1/3

Step 5

Decimal & Percentage Representation

Dividing the numerator 1 by denominator 3 produces a repeating decimal (approximately 0.333333, or 33.3333%).

1 ÷ 3 = 0.333333 (33.3333%)

Visual Representation

The diagram below illustrates 4/28 plus 4/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`1/3`
Mixed Number Form	`1/3`
Decimal Form	`0.333333`
Percentage	`33.3333%`

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Frequently Asked Questions

What is 4/28 plus 4/21 as a fraction?

4/28 + 4/21 in simplest fraction form is 1/3.

What is 4/28 plus 4/21 as a decimal?

4/28 + 4/21 converted to a decimal is 0.333333.

What is 4/28 plus 4/21 as a percentage?

4/28 + 4/21 expressed as a percentage is 33.3333%.

Does 4/28 plus 4/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.333333...) because the denominator contains prime factors other than 2 and 5.