This resource is based on two aspects of the design of bar codes used for products on sale in shops. The first aspect is that of a check digit and how it works; the second aspect is that of the actual design for the strips of numbers that make up bar codes. This activity only deals with the left-hand side numbers in eight digit codes but this can be easily extended to thirteen digit codes and right-hand code designs.
Number Bar code Overview outlines the content of the resource and suggests possible extensions.
In Number Bar code Guidance, background information is given about possible uses of bar codes and some explanation about their structure. In particular, the check digit is explained and the fact that different codes are used for digits in different parts of the bar code. There are links to cimt resources including an interactive bar code generator.
Number Bar code DataSheet shows the code for left-hand side digits 0-9.
Number Bar code Handout for students has clear explanation for finding the check digit and two questions to confirm understanding. There is clear explanation of how the left hand side digits are generated and students are asked to confirm that the seven module design is sufficient to generate each digit.