If possible without calculating: Tell whether the fraction is a lowest terms fraction.

Simplify (or reduce) a fraction by dividing both the *numerator* and the *denominator* by the simplification number.

A lowest terms fraction can not be simplified further.

If you would like to have a vivid explanation with a detailed example, please read the page Simplifying/Reducing Fractions - Learn this magic trick!

**Step 1: Test, if the numerator or the denominator is equal to 1.**

If the numerator or the denominator is equal to 1, the fraction is simplified to lowest terms.

Since this is not the case, go on to the next test:

**Step 2: Test, if the numerator or the denominator is a prime number**

If the numerator or the denominator is a prime number and they are **not multiples**, the fraction is simplified to lowest terms!

In this case the numerator (19) is a prime number.

Since the numerator (19) and the denominator (171) are multiples, the fraction can be simplified further, namely the number

*19*.