Identify unit fractions
for 3rd grade

Identify unit fractions

A unit fraction is the name given to a fraction where the numerator (the number on top) is 1.

So ½ is a unit fraction as is ⅐ and ⅛ but ⅖ is not because it's numerator is not 1, it is 2.

One reason unit fractions are interesting is because they are the reverse of the "integers" (that is, the whole numbers). When integers are written as fractions they are always the integer value over 1. So 2 is written 2/1 and 3 is written 3/1.

Another interesting fact is that if you multiply ½ by 2/1 you get 1, and this is always true when you multiply an integer as fraction by it's inverse unit fraction. If you think about it, it is quite intuitive: half of 2 is 1 and one third of three is 1, and a quarter of 4, etc., they are always 1.

Actually, you can expand that rule to say that any fraction multiplied by itself reversed will equal 1.

This topic asks you to identify unit fractions, but also fractions that can be simplified to unit fractions. To simplify a fraction, you divide both it's numerator and it's denominator by the same number. For instance, 3/9 (three ninths) can be simplified by dividing both numerator and denominator by 3 to give 1/3 (one third). Three ninths and one third are called equivalent fraction because of this, and if you think of three ninths of a number compared to one third of a number, you will see that the answer is the same.