LESSON 2 Wholes and Parts

Irma told her friends that she ate half of a cake yesterday. They all had a different idea about what that meant.

  1. If each student shown here is thinking of of a cake, why are all the pieces of cake different sizes?

Numerators and Denominators

The numerator and denominator of a fraction work together to tell the size of the number represented by the fraction.

The denominator of a fraction tells us to divide the whole into that many equal parts. The 4 in the fraction shown above tells us to divide the whole into four equal parts (fourths).

The numerator tells us the number of parts to consider, so the 3 tells us we are interested in three of the parts.