What is 11/18 plus 2/3? (Answer: 23/18)

Exact Answer

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Problem: What is 11/18 plus 2/3?
Formula / Expression: 11/18 + 2/3
Final Answer: 1 5/18 (23/18)
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Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
Notice that 18 is an exact multiple of 3 (3 × 6 = 18). The Least Common Denominator (LCD) is simply 18, meaning we only need to scale one fraction.
Working: LCD(18, 3) = 18

Step 2: Convert to Equivalent Fractions with Common Denominator 18
Multiply the numerator and denominator of 11/18 by 1, and multiply the numerator and denominator of 2/3 by 6 so both fractions share the common base 18.
Working: 11 × 1/18 × 1 = 11/18 and 2 × 6/3 × 6 = 12/18

Step 3: Add the Numerators
Now add the numerators (11 + 12 = 23) and keep the common denominator 18 unchanged.
Working: 11 + 12/18 = 23/18

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 23 and 18 is 1, confirming that 23/18 cannot be reduced further—it is already in its simplest irreducible form.
Working: 23/18

Step 5: Convert Improper Fraction to a Mixed Number
Since the numerator (23) is greater than the denominator (18), divide 23 by 18: it goes in 1 whole time(s) with a remainder of 5, giving the mixed number 1 5/18.
Working: 23/18 = 1 5/18

Step 6: Decimal & Percentage Representation
Dividing the numerator 23 by denominator 18 produces a repeating decimal (approximately 1.277778, or 127.7778%).
Working: 23 ÷ 18 = 1.277778 (127.7778%)

Key Values:
- Simplified Fraction: 23/18
- Mixed Number Form: 1 5/18
- Decimal Value: 1.277778
- Percentage: 127.7778%

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Solved with FractionsCalc:
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11/18 + 2/3 = 23/18

Simplified Fraction

23/18

Mixed Number

1 5/18

Decimal Value

1.277778

Percentage

127.7778%

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Step-by-Step Solution: 11/18 + 2/3

Step 1

Find the Least Common Denominator (LCD)

Notice that 18 is an exact multiple of 3 (3 × 6 = 18). The Least Common Denominator (LCD) is simply 18, meaning we only need to scale one fraction.

LCD(18, 3) = 18

Step 2

Convert to Equivalent Fractions with Common Denominator 18

Multiply the numerator and denominator of 11/18 by 1, and multiply the numerator and denominator of 2/3 by 6 so both fractions share the common base 18.

11 × 1/18 × 1 = 11/18 and 2 × 6/3 × 6 = 12/18

Step 3

Add the Numerators

Now add the numerators (11 + 12 = 23) and keep the common denominator 18 unchanged.

11 + 12/18 = 23/18

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 23 and 18 is 1, confirming that 23/18 cannot be reduced further—it is already in its simplest irreducible form.

23/18

Step 5

Convert Improper Fraction to a Mixed Number

Since the numerator (23) is greater than the denominator (18), divide 23 by 18: it goes in 1 whole time(s) with a remainder of 5, giving the mixed number 1 5/18.

23/18 = 15/18

Step 6

Decimal & Percentage Representation

Dividing the numerator 23 by denominator 18 produces a repeating decimal (approximately 1.277778, or 127.7778%).

23 ÷ 18 = 1.277778 (127.7778%)

Visual Representation

The diagram below illustrates 11/18 plus 2/3 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`23/18`
Mixed Number Form	`1 5/18`
Decimal Form	`1.277778`
Percentage	`127.7778%`

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Frequently Asked Questions

What is 11/18 plus 2/3 as a fraction?

11/18 + 2/3 in simplest fraction form is 23/18 (or 1 5/18 as a mixed number).

What is 11/18 plus 2/3 as a decimal?

11/18 + 2/3 converted to a decimal is 1.277778.

What is 11/18 plus 2/3 as a percentage?

11/18 + 2/3 expressed as a percentage is 127.7778%.

How do you write 11/18 plus 2/3 as a mixed number?

Because the numerator is greater than the denominator, the improper fraction 23/18 can be written as the mixed number 1 5/18.

Does 11/18 plus 2/3 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 1.277778...) because the denominator contains prime factors other than 2 and 5.