# 2.0.1 What to Expect in this Unit

This unit should take around eight hours to complete. In this unit you will learn about:

• The history of numbers.
• How we put numbers together including decimals.
• Number lines and how to use them.
• Rounding numbers and estimating.

As with any language, we will start with the basics. In Section 1, we will explore the history of numbers, including the use of “placeholders” and decimals. It may surprise you to learn that our number system continues to develop even today.

In Section 2, the main focus will be reading and using a number line. Whether you are practicing writing numbers or participating in a competition to see whose flower grows the tallest, you will continue to develop the skills you need to perform future calculations in this section.

In Section 3, you will study rounding, which will help you give appropriate answers to questions and make good estimates of the correctness of your answer. In the sciences especially, rounding can significantly affect your answer, and that is something you need to be aware of. For example, as a nurse, you wouldn’t want to administer a dangerous amount of medication to a patient over a certain period of time!

2.0.2 Where Do You See Numbers?