What is 7/12 plus 9/13? (Answer: 199/156)

Exact Answer

==================================================
Problem: What is 7/12 plus 9/13?
Formula / Expression: 7/12 + 9/13
Final Answer: 1 43/156 (199/156)
==================================================

Step-by-Step Solution:

Step 1: Find the Least Common Denominator (LCD)
The denominators 12 and 13 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 12 × 13 = 156.
Working: LCD(12, 13) = 156

Step 2: Convert to Equivalent Fractions with Common Denominator 156
Multiply the numerator and denominator of 7/12 by 13, and multiply the numerator and denominator of 9/13 by 12 so both fractions share the common base 156.
Working: 7 × 13/12 × 13 = 91/156 and 9 × 12/13 × 12 = 108/156

Step 3: Add the Numerators
Now add the numerators (91 + 108 = 199) and keep the common denominator 156 unchanged.
Working: 91 + 108/156 = 199/156

Step 4: Check if the Fraction Can Be Simplified
The Greatest Common Divisor (GCD) of 199 and 156 is 1, confirming that 199/156 cannot be reduced further—it is already in its simplest irreducible form.
Working: 199/156

Step 5: Convert Improper Fraction to a Mixed Number
Since the numerator (199) is greater than the denominator (156), divide 199 by 156: it goes in 1 whole time(s) with a remainder of 43, giving the mixed number 1 43/156.
Working: 199/156 = 1 43/156

Step 6: Decimal & Percentage Representation
Dividing the numerator 199 by denominator 156 produces a repeating decimal (approximately 1.275641, or 127.5641%).
Working: 199 ÷ 156 = 1.275641 (127.5641%)

Key Values:
- Simplified Fraction: 199/156
- Mixed Number Form: 1 43/156
- Decimal Value: 1.275641
- Percentage: 127.5641%

--------------------------------------------------
Solved with FractionsCalc:
https://fractionscalc.com/what-is-7-12-plus-9-13/
==================================================

7/12 + 9/13 = 199/156

Simplified Fraction

199/156

Mixed Number

1 43/156

Decimal Value

1.275641

Percentage

127.5641%

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: 7/12 + 9/13

Step 1

Find the Least Common Denominator (LCD)

The denominators 12 and 13 are coprime (they share no common factors other than 1). Therefore, their Least Common Denominator (LCD) is simply their direct product: 12 × 13 = 156.

LCD(12, 13) = 156

Step 2

Convert to Equivalent Fractions with Common Denominator 156

Multiply the numerator and denominator of 7/12 by 13, and multiply the numerator and denominator of 9/13 by 12 so both fractions share the common base 156.

7 × 13/12 × 13 = 91/156 and 9 × 12/13 × 12 = 108/156

Step 3

Add the Numerators

Now add the numerators (91 + 108 = 199) and keep the common denominator 156 unchanged.

91 + 108/156 = 199/156

Step 4

Check if the Fraction Can Be Simplified

The Greatest Common Divisor (GCD) of 199 and 156 is 1, confirming that 199/156 cannot be reduced further—it is already in its simplest irreducible form.

199/156

Step 5

Convert Improper Fraction to a Mixed Number

Since the numerator (199) is greater than the denominator (156), divide 199 by 156: it goes in 1 whole time(s) with a remainder of 43, giving the mixed number 1 43/156.

199/156 = 143/156

Step 6

Decimal & Percentage Representation

Dividing the numerator 199 by denominator 156 produces a repeating decimal (approximately 1.275641, or 127.5641%).

199 ÷ 156 = 1.275641 (127.5641%)

Visual Representation

The diagram below illustrates 7/12 plus 9/13 visually:

Summary & Alternative Representations

Property / Format	Value
Lowest Terms Fraction	`199/156`
Mixed Number Form	`1 43/156`
Decimal Form	`1.275641`
Percentage	`127.5641%`

Was this solution helpful?

Help us improve our free step-by-step tools

Frequently Asked Questions

What is 7/12 plus 9/13 as a fraction?

7/12 + 9/13 in simplest fraction form is 199/156 (or 1 43/156 as a mixed number).

What is 7/12 plus 9/13 as a decimal?

7/12 + 9/13 converted to a decimal is 1.275641.

What is 7/12 plus 9/13 as a percentage?

7/12 + 9/13 expressed as a percentage is 127.5641%.

How do you write 7/12 plus 9/13 as a mixed number?

Because the numerator is greater than the denominator, the improper fraction 199/156 can be written as the mixed number 1 43/156.

Does 7/12 plus 9/13 result in a terminating or repeating decimal?

It results in a repeating decimal (approximately 1.275641...) because the denominator contains prime factors other than 2 and 5.