Algebraic fractions

Rational Expressions Calculator

Type two algebraic fractions — x/3 + 1/6, x/4 + x/6, 2x/5 + x/3 — and the calculator finds the least common denominator, rewrites each term, combines like terms, and simplifies, naming every rule it uses.

  • add algebraic fractions
  • least common denominator with letters
  • combine like terms
  • one bar, one answer
Start with simplifying rational expressions

Algebra addition tool

Add fractions that carry a variable

Type two terms with the same variable — the tool finds the common denominator and combines the numerators step by step.

Type the full expression

Examples: x/3 + 1/6, x/4 + x/6, 2x/5 + x/3, or 1/2 + x/8.

Derivation

x/4 + x/6

= 3x/12 + 2x/12

= 5x/12

What it computes

Two terms in, one simplified fraction out

CapabilityHow it worksExample
Add two algebraic fractionsTerms like x/3, 2x/5, and plain fractions combine over their least common denominator, with like terms merged.x/4 + x/6 = 5x/12
Unlike variables and coefficientsCoefficients scale during the rewrite — 2x/5 becomes 6x/15 — and unlike terms keep their sum: (6x + 2)/15.2x/5 + x/3 = 11x/15
Mixed numeric and variable termsOne term with x and one without still shares a bar: the answer is a sum over the common denominator.x/3 + 1/6 = (2x + 1)/6
Simplification afterwardsWhen both numerator terms share a factor with the denominator, the result reduces: 3x/12 simplifies to x/4.x/4 + x/6 → 5x/12

Worked example

Like variable terms: x/4 + x/6

x/4 + x/6 = 3x/12 + 2x/12 = 5x/12

The least common denominator of 4 and 6 is 12. Both numerators carry an x, so after the rewrite they merge: 3x + 2x = 5x. The variable never touched the denominator work.

Worked example

Coefficients scale in the rewrite: 2x/5 + x/3

2x/5 + x/3 = 6x/15 + 5x/15 = 11x/15

Stretching 2x/5 to fifteenths multiplies the whole numerator by 3 — 6x, not 2x. The full numerator feels the same stretch the denominator does.

Worked example

Unlike terms keep their sum: x/3 + 1/6

x/3 + 1/6 = 2x/6 + 1/6 = (2x + 1)/6

One numerator has an x and the other does not, so 2x and 1 cannot merge. The single bar over 2x + 1 is the finished answer — no further simplification exists.

Worked example

The result reduces: x/3 + x/6

x/3 + x/6 = 2x/6 + x/6 = 3x/6 = x/2

The combined numerator 3x and denominator 6 share the factor 3, so the sum reduces to x/2. Simplify variable fractions exactly as numeric ones — divide top and bottom by the shared factor.

What the calculator does inside

For x/4 + x/6, the calculator finds the least common denominator of 4 and 6 — twelve — and rewrites each term in that unit: 3x/12 and 2x/12. The numerators are like terms (both count x’s), so they merge to 5x, and the answer 5x/12 is checked for reduction before it is shown. Nothing about the variable changed the denominator work; twelfths are twelfths whether or not an x rides on top.

For deeper work — subtracting variable fractions, simplifying products like 2x/3 × 6/x², or solving equations whose variable sits under the bar — the guides below walk the same rules by hand, and the tools on those pages verify each result.

Common questions

Rational Expressions Calculator FAQ

It adds two algebraic fractions — terms like x/3, 2x/5, x/4 + x/6, or 1/2 + x/8 — over their least common denominator, combining like terms and simplifying the result one step at a time.