What is 3/8 plus 7/18? (Answer: 55/72)

Exact Answer

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Problem: What is 3/8 plus 7/18?
Formula / Expression: 3/8 + 7/18
Final Answer: 55/72
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 8 and 18 share a common factor (GCD = 2). Finding their Least Common Multiple gives an LCD of 72 (which is smaller than their product 8 × 18 = 144, keeping the calculation simpler).
Working: LCD(8, 18) = 72

Step 2: Convert to Equivalent Fractions with Common Denominator 72
Multiply the numerator and denominator of 3/8 by 9, and multiply the numerator and denominator of 7/18 by 4 so both fractions share the common base 72.
Working: 3 × 9/8 × 9 = 27/72 and 7 × 4/18 × 4 = 28/72

Step 3: Add the Numerators
Now add the numerators (27 + 28 = 55) and keep the common denominator 72 unchanged.
Working: 27 + 28/72 = 55/72

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 55 and 72 is 1, confirming that 55/72 cannot be reduced further—it is already in its simplest irreducible form.
Working: 55/72

Step 5: Decimal & Percentage Representation
Dividing the numerator 55 by denominator 72 produces a repeating decimal (approximately 0.763889, or 76.3889%).
Working: 55 ÷ 72 = 0.763889 (76.3889%)

Key Values:
- Simplified Fraction: 55/72
- Mixed Number Form: 55/72
- Decimal Value: 0.763889
- Percentage: 76.3889%

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Solved with FractionsCalc:
https://fractionscalc.com/what-is-3-8-plus-7-18/
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3/8 + 7/18 = 55/72

Simplified Fraction

55/72

Mixed Number

Proper (55/72)

Decimal Value

0.763889

Percentage

76.3889%

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Step-by-Step Solution: 3/8 + 7/18

Step 1

Find the Least Common Denominator (LCD)

The denominators 8 and 18 share a common factor (GCD = 2). Finding their Least Common Multiple gives an LCD of 72 (which is smaller than their product 8 × 18 = 144, keeping the calculation simpler).

LCD(8, 18) = 72

Step 2

Convert to Equivalent Fractions with Common Denominator 72

Multiply the numerator and denominator of 3/8 by 9, and multiply the numerator and denominator of 7/18 by 4 so both fractions share the common base 72.

3 × 9/8 × 9 = 27/72 and 7 × 4/18 × 4 = 28/72

Step 3

Add the Numerators

Now add the numerators (27 + 28 = 55) and keep the common denominator 72 unchanged.

27 + 28/72 = 55/72

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 55 and 72 is 1, confirming that 55/72 cannot be reduced further—it is already in its simplest irreducible form.

55/72

Step 5

Decimal & Percentage Representation

Dividing the numerator 55 by denominator 72 produces a repeating decimal (approximately 0.763889, or 76.3889%).

55 ÷ 72 = 0.763889 (76.3889%)

Visual Representation

The diagram below illustrates 3/8 plus 7/18 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`55/72`
Mixed Number Form	`55/72`
Decimal Form	`0.763889`
Percentage	`76.3889%`

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Frequently Asked Questions

What is 3/8 plus 7/18 as a fraction?

3/8 + 7/18 in simplest fraction form is 55/72.

What is 3/8 plus 7/18 as a decimal?

3/8 + 7/18 converted to a decimal is 0.763889.

What is 3/8 plus 7/18 as a percentage?

3/8 + 7/18 expressed as a percentage is 76.3889%.

Does 3/8 plus 7/18 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.763889...) because the denominator contains prime factors other than 2 and 5.