A drawing at a 1:500 scale indicates that 1 unit on the drawing corresponds to 500 units in reality.

To elaborate, a scale drawing is a technique used to depict large objects or areas on a smaller, more manageable piece of paper. The scale provides a ratio that indicates how much smaller the representation is compared to the actual object. Specifically, in a 1:500 scale, every 1 unit of measurement on the drawing (such as $1$ centimetre or $1$ inch) represents $500$ of the same units in the real world.

For instance, if you measure a length of $2$ centimetres on the drawing, this means that the actual length is calculated as $2$ centimetres multiplied by $500$, resulting in $1000$ centimetres, or $10$ metres. This scaling method proves particularly beneficial in fields like architecture, engineering, and geography, where it is impractical to create full-size representations of buildings, roads, or landscapes.

To accurately interpret a 1:500 scale drawing, familiarity with basic multiplication and unit conversions is essential. If you encounter a measurement on the drawing, you simply multiply it by $500$ to determine the corresponding real-world size. Conversely, if you know the actual size and wish to find out how it is represented on the drawing, you divide by $500$.

Mastering the concept of scale drawings is an important skill in GCSE Maths, as it enables you to visualize and analyze real-world objects and spaces in a simplified yet precise manner.