# Fractions & Decimals

### Topics

**Fractions** may look funky at first, but they’re actually really cool and useful once you get the hang of them.

The great news is, you’re already a pro at fractions. You’ve been thinking about fractions since your rugrat days (even if you didn’t know it). Want proof?

You call out times like “quarter past two” or “half past three.” You know how to split up a pizza into thirds, so you and your two friends all get equal amounts. You've used measuring tapes for building, measuring cups and tablespoons for baking. All fractions.

Fractions are just a simple way to speak of **parts of a whole** object, like parts of an hour, parts of a sandwich, or parts of a dollar.

## Fractions Vocabulary

**Numerator:**the top number of a fraction.

**Denominator:**the bottom number of a fraction.**Mixed Number:**a number expressed as a whole number and a fraction, like or .**Improper Fraction:**a fraction in which the numerator is larger than the denominator, like or .**Reciprocal:**an inverse fraction. Flip the numerator and denominator. and are reciprocal fractions.

## Visualizing Fractions

Start with a circle to represent 1 whole.

If we divide this circle in 2 equal pieces, we get two 's.

Divide it into 3 equal pieces, and we get three 's.

Divide it into 4 equal pieces and we get four 's.

**See what we mean? If you know pizza, you know fractions.**

**Fifths**

**Sixths**

**Sevenths**

Let's also try to visualize these fractions on a number line. Here we have a number line stretching from 0 to 1.

If we divide it in half, we get two parts, or halves:

Here it is divided into thirds:

Fourths:

Fifths:

Sixths:

And Eighths:

All together now!