An introduction to positive and negative numbers. Cartoon-style numbers initially form a line from 0 to 9. The negative numbers 1 to -9 then join the line in the correct sequence. The clip continues with 3 added to -7, and then added to -4, and so on, to show how the result of the addition becomes more positive each time.

First broadcast:
14 September 2007

Students could place numbers from -10 to 10 in a hat and select a number at random. Students could then organise themselves in order from the lowest number to the highest.