Fraction Reducer – Simplify to Lowest Terms
Reduce any fraction via GCD: 84/126 → GCD 42 → 2/3.
- Euclid steps, improper fractions and the decimal value 0.667 all shown.
Figures are estimates from this calculator’s standard formula — adjust the inputs in the tool below for your exact number.
How the Fraction Reducer Works
Reducing a fraction divides top and bottom by their greatest common divisor, leaving an equivalent fraction that is easier to read and compute with. For 84/126, Euclid’s algorithm finds the GCD quickly: 126 mod 84 = 42, then 84 mod 42 = 0, so g = 42. Dividing gives 84÷42 = 2 and 126÷42 = 3, hence 2/3. The reducer prints these Euclid steps so the method is transparent, handles improper fractions (99/45 → 11/5) and negatives (−18/24 → −3/4, sign carried on top), and shows the decimal value (2/3 = 0.666…) so you can confirm nothing changed but the form. When the GCD is 1 the fraction is already fully reduced, as with 8/15. Reducing first also prevents overflow when the fraction later feeds into multiplication or addition problems.
- 1
Enter numerator and denominator
Any integers, including negative or improper fractions
- 2
Run Euclid’s algorithm
The GCD steps are printed: GCD(84,126) → GCD(126,84)... shows 42
- 3
Divide both parts
Top and bottom are divided by the GCD
- 4
Confirm equivalence
The decimal value of both forms is displayed side by side
Use Cases
Homework Cleanup
Turn messy answers like 84/126 into 2/3 before submitting
Cooking Math
A recipe scaled to 12/8 cups reduces to 1½ cups
Probability
Odds like 36/52 simplify to 9/13 for clear reporting
Tips
- 1
Divide numerator AND denominator — changing one alters the value
- 2
GCD = 1 means the fraction is already in lowest terms
- 3
Reducing before multiplying keeps numbers small: (84/126)(10/14) → (2/3)(5/7)
Common Mistakes
Dividing only the numerator, silently changing the value
Stopping at a common divisor instead of the greatest one: 84/126 → 14/21 → 2/3 wastes a step
Dropping the negative sign when reducing −18/24
Reducing across an addition: in 1/2 + 1/4 you cannot cancel the 2 and 4
FAQs
What is 84/126 in lowest terms?
How does Euclid’s algorithm find the GCD?
Is 8/15 already reduced?
What is 99/45 reduced?
Can I reduce −18/24?
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