Simplify fractions calculator
Enter a numerator and denominator and the calculator reduces the fraction to lowest terms, showing what it divided by.
The fraction 84/126 divides by 42 to give 2/3.
Formula
HCF is the highest common factor of the numerator and denominator. Dividing both by it gives lowest terms in a single step.
How we got there
A fraction is in lowest terms when the HCF of its numerator and denominator is 1 — there is nothing left to divide by.
How to simplify a fraction by hand
- Find the HCF of the numerator and denominator
For 84 and 126 the highest common factor is 42.
- Divide both by the HCF
84 ÷ 42 = 2 and 126 ÷ 42 = 3.
- Write down the answer
84/126 = 2/3. That fraction cannot be reduced any further.
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Frequently asked questions
Divide the numerator and denominator by their highest common factor. For 84/126 the HCF is 42, giving 2/3.
When the HCF of the numerator and denominator is 1 — they share no factor greater than one.
Yes, dividing by 2, then 3 and so on. Dividing by the HCF straight away is simply quicker.
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