a tool to promote the understanding of our number system from 10 to 1000.

The virtual tool is the reprogramming and extension of the app “Numbers up to 100”.
The app allows you to display quantities and numbers on a

• Ten-Field,
• Twenty-field and on a
• Hundred field

can be displayed. In addition, an interactive number (changeable digit by digit), a number line, place value materials (Dienes blocks), and various verbal representations of numbers can be shown or hidden. Unlike the Calculation Field This field is about the representation and rapid recognition of numbers and quantities in the hundreds field. This learning tool is particularly suitable for children who do not yet have a solid understanding of the place value system and still have difficulty counting numbers one by one.

The video presents the number field in the version of a hundred field.

Possible activities

Basically, using the app in class is useful when the child has already had hands-on experience with quantities, i.e. counting concrete quantities, laying them on a real field, bundling them into tens, laying them with place value material, etc. It is intended to help children to explore the underlying structure of numbers and also to understand the distinction between tens and ones. For example, the following exercises can be carried out:

• Place a given number on the field as quickly as possible (by clicking on the corresponding field). You can check the result yourself by covering the number (pulling up the cover).
• Flash view exercise: Quickly name the corresponding numerical value for a given quantity.
• The aim is to change the amount of a given or placed number with as few clicks as possible so that a new amount is created. This can also be done on the iconic level (by inserting or deleting tiles) or on the symbolic level (by changing the place value numbers by pulling the numbers up and down). The aim is to use insertion/removal in tens as cleverly as possible.
• Find out by trial and error which regular action underlies an operative series of numbers (e.g. 12, 22, 32, 42, ...).
• compare number wordsShow the number word and the logical number word. Form the number 54. Compare both ways of writing it. How does the logical number word work? Which one do you find easier to read? Why?
• Courses of action document (Number range) 1000): Turn on the arrow display. Try to get from 200 to 365. How many steps does it take? Is there a shorter way? Press the restart button and try a different approach.
• Display only the place value material and increment the tens. What happens when the tenth tens rod is inserted?
• …

Have fun experimenting and learning with the app!

In a Task card , I am collecting teaching ideas for using the app (almost in german language, sorry). So far, these are more like rough ideas that will be further developed and refined, and they will also be supplemented with templates, interactive exercises, and explanatory videos. I would be very happy if others would also post their ideas on the board through the plus sign or use the comment function, creating a collection of exciting usage scenarios.

Unfortunately only for iOS / macOS
Unfortunately, the app is only available for Apple devices. Online calculation fields with a slightly reduced range of functions that can be executed without installation are available here.

A web version for displaying numbers up to 9999 is also available. Numbers can be set and displayed automatically. Ones are represented by tapping (also with multiple fingers simultaneously), tens by drawing a line (also possible with multiple fingers simultaneously), and hundreds by drawing a square/rectangle.
https://lernsoftware-mathematik.de/zahlen/