Students count on and count back, using a variety of numbers. The activity includes negative numbers if you wish.
http://www.mathsframe.co.uk/sequences.swf

Other resources by this author can be found at:
http://www.mathsframe.co.uk/free_resources.asp

Place positive whole numbers, negative whole numbers, decimals, fractions and multiples on a number line.
http://www.mathsframe.co.uk/placenumbers.swf

Other resources from the same author can be found at
http://www.mathsframe.co.uk/free_resources.asp

This is an early introduction to fractions, looking at halves, thirds and quarters only.

http://www.ngfl-cymru.org.uk/vtc/ngfl/ngfl-flash/fractions/index.htm

Estimate the number that the pointer is pointing to, and then reveal the correct answer. You can choose whole numbers or decimals, and create your own number line if you wish. Click on [Begin] to start.

http://resources.oswego.org/games/Estimate/estimate.html

Put either a "less than" symbol or a "greater than" symbol between the two numbers. You can choose the range (1 - 100, 1 - 1,000 or 1 - 10,000).

http://www.crickweb.co.uk/assets/resources/flash.php?&file=ncmenu

Some lovely interactive number grids.

1-100
http://www.oswego.org/ocsd-web/games/SplatSquares/splatsq100.html

0-99
http://www.oswego.org/ocsd-web/games/SplatSquares/splatsq99.html

1-100 Reveal
http://www.oswego.org/ocsd-web/games/SplatSquares/splatre100.html

0-99 Reveal
http://www.oswego.org/ocsd-web/games/SplatSquares/splatre99.html

Can you locate the 10 numbers on the 100-grid in less than one minute?

http://www.oswego.org/ocsd-web/games/DogBone/gamebone.html

An interactive 100 square. You can choose to start the square with either 0 or 1.
http://www.hellam.net/maths2000/100square.html

You can also change the 'width' of the 100 board using this link:
http://www.hellam.net/maths2000/nsquare.html

Here is a different 100 square. Clink on the IDEAS button to see how you might use this tool.
http://www.amblesideprimary.com/ambleweb/mentalmaths/countersquare.html

This is a Promethean ActivBoard Resource Pack for teaching counting and sorting. It has a number of themes including a birthday cake and candles, chickens, fish, ladybirds, lollipops and many more.

Each theme contains a completed flipchart page, a background, “decorative images” and images to count or sort. You will also find a folder with sample sorting boxes including pre-done pages, individual boxes and groups of boxes.

The flipchart can be found here:
http://www.prometheanplanet.com/uk/server/show/ConResource.13732

If you are not yet a member of Promethean Planet, you will first have to register here:
http://www.prometheanplanet.com/uk/server/show/nav.914

An interactive activity for those littlies who are just learning the digits.
http://www.poissonrouge.com/bigfish/en/numbers.html