These number expanders are used to teach place value for numbers up to 9999. Whether you print and laminate or just use it as a paper version, this is a great way to teach the place value of digits in a number. Simply print and fold on all the black lines so that the yellow boxes come together. Write the numbers in the yellow boxes. As you pull open parts of the expander, it will show how many ones, tens, hundreds and thousands are in a particular number.