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PLACE VALUE AND NUMBER NAMES



Unit Overview

This unit focuses on place value.  We will explore the various ways you can express a number. 

 

Place Value and Number Names

Below is a model for the ones, tens and hundreds.





The Ten Digits

The Digits we use today are called "Hindu-Arabic Numerals" and look like these:

0   1   2   3   4   5   6   7   8   9

We can use these on their own to count up to 9:



But what happens after 9?

Ten or More

When we have more than 9 items, we start another column - the "tens" column - and we write down how many "tens" we have, followed by how many "ones" (also called "units").

Example: this is how we write down twelve:


It says we have 1 Ten and 2 Ones, which makes 12.


This can also be written as 1 × 10 + 2 × 1.


Example: "35" means 3 Tens and 5 Ones, which is also 3 × 10 + 5 × 1


 


Zero

What if we have 1 Ten, but no Ones? We show "no Ones" by putting a zero there:


We have to put a Zero in the Ones place or "10" looks like "1".


 


A Hundred or More

When we have more than 99 items, we start another column - the "hundreds" column. Now we need to show how many Hundreds, Tens and Ones:



That shows we have 1 Hundred, 4 Tens and 3 Ones:

This can also be written as 1 × 100 + 4 × 10 + 3 × 1.


Names of Each Column

Each time we want to show a bigger number we just add one column to the left and we know it is always 10 times bigger than the column on its right.  


Each new column on the left is ten times bigger! So, where we PLACE a digit is important!


These are the names of each column:





Click on the link to watch the video "Finding a number's place value".


 


Student Practice

  Base Ten Worksheet
   
  Expanded Form Worksheet