What is 18/51 plus 8/21? (Answer: 262/357)

Exact Answer

==================================================
Problem: What is 18/51 plus 8/21?
Formula / Expression: 18/51 + 8/21
Final Answer: 262/357
==================================================

Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 51 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 357 (which is smaller than their product 51 × 21 = 1071, keeping the calculation simpler).
Working: LCD(51, 21) = 357

Step 2: Convert to Equivalent Fractions with Common Denominator 357
Multiply the numerator and denominator of 18/51 by 7, and multiply the numerator and denominator of 8/21 by 17 so both fractions share the common base 357.
Working: 18 × 7/51 × 7 = 126/357 and 8 × 17/21 × 17 = 136/357

Step 3: Add the Numerators
Now add the numerators (126 + 136 = 262) and keep the common denominator 357 unchanged.
Working: 126 + 136/357 = 262/357

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 262 and 357 is 1, confirming that 262/357 cannot be reduced further—it is already in its simplest irreducible form.
Working: 262/357

Step 5: Decimal & Percentage Representation
Dividing the numerator 262 by denominator 357 produces a repeating decimal (approximately 0.733894, or 73.3894%).
Working: 262 ÷ 357 = 0.733894 (73.3894%)

Key Values:
- Simplified Fraction: 262/357
- Mixed Number Form: 262/357
- Decimal Value: 0.733894
- Percentage: 73.3894%

--------------------------------------------------
Solved with FractionsCalc:
https://fractionscalc.com/what-is-18-51-plus-8-21/
==================================================

18/51 + 8/21 = 262/357

Simplified Fraction

262/357

Mixed Number

Proper (262/357)

Decimal Value

0.733894

Percentage

73.3894%

Reduce / Convert Fraction:

Convert Fraction:

Enter Decimal Number:

Enter Percentage: %

What is % of

From Value: To Value:

Simplify Ratio: :

Switch to Proportion / Missing X Solver (A/B = C/D) →

Enter 3 known numbers and leave 1 empty (or type x) to solve:

← Switch to Ratio Simplifier (A:B)

Provide any 2 values below to calculate the remaining:

Price before discount

Discount

Price after discount

You saved

+ Add Sales Tax & Extra Coupon (Optional)

Sales Tax: % Extra Off: %

Provide any 2 values below to calculate the remaining:

Cost

Markup

REVENUE

Gross Profit

Profit Margin

Bill Subtotal

Tip Percentage

Split (People)

👥

Quick Tip:

Total Bill

Split Between

👥

Tip % (Optional)

Include Tip:

Total Price

Quantity

Unit of Measure

← Discount & Sales Tax • Ratio Simplifier (A:B) →

First Number: Second Number:

Find All Factors of:

Dividend: ÷ Divisor:

Number to Round: To Nearest:

Method: Standard (5+ ↑) Always Up (Ceil) Always Down (Floor)

Presets:

√ Square Root of: OR Power (x^y): ^{^}

x² + x + = 0

Number (n! & log):

Circle Radius (r):

Side a: Side b:

Angle (Degrees): °

Numbers (comma separated):

Total Items (n): Choose (r):

Decimal Number:

Number (1–3999):

Step-by-Step Solution: 18/51 + 8/21

Step 1

Find the Least Common Denominator (LCD)

The denominators 51 and 21 share a common factor (GCD = 3). Finding their Least Common Multiple gives an LCD of 357 (which is smaller than their product 51 × 21 = 1071, keeping the calculation simpler).

LCD(51, 21) = 357

Step 2

Convert to Equivalent Fractions with Common Denominator 357

Multiply the numerator and denominator of 18/51 by 7, and multiply the numerator and denominator of 8/21 by 17 so both fractions share the common base 357.

18 × 7/51 × 7 = 126/357 and 8 × 17/21 × 17 = 136/357

Step 3

Add the Numerators

Now add the numerators (126 + 136 = 262) and keep the common denominator 357 unchanged.

126 + 136/357 = 262/357

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 262 and 357 is 1, confirming that 262/357 cannot be reduced further—it is already in its simplest irreducible form.

262/357

Step 5

Decimal & Percentage Representation

Dividing the numerator 262 by denominator 357 produces a repeating decimal (approximately 0.733894, or 73.3894%).

262 ÷ 357 = 0.733894 (73.3894%)

Visual Representation

The diagram below illustrates 18/51 plus 8/21 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`262/357`
Mixed Number Form	`262/357`
Decimal Form	`0.733894`
Percentage	`73.3894%`

Was this solution helpful?

Help us improve our free step-by-step tools

Frequently Asked Questions

What is 18/51 plus 8/21 as a fraction?

18/51 + 8/21 in simplest fraction form is 262/357.

What is 18/51 plus 8/21 as a decimal?

18/51 + 8/21 converted to a decimal is 0.733894.

What is 18/51 plus 8/21 as a percentage?

18/51 + 8/21 expressed as a percentage is 73.3894%.

Does 18/51 plus 8/21 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 0.733894...) because the denominator contains prime factors other than 2 and 5.