Imagine I'm queuing upwards to purchase 4 items of clothing, which cost £29.95, £49.95, £59.95 in addition to £99.95. To hold upwards past times fourth dimension I determine to function out the hateful cost of these 4 items. To brand the numbers easier to bargain with, I add together 5p to each total in addition to and so separate past times 10, giving me £3, £5, £6 in addition to £10. It's really slow to function out the hateful of these 'coded' prices inward my caput - it's £6. And right away I tin uncode that hateful past times multiplying past times 10 in addition to so subtracting 5p (the inverse of the master copy coding). That rapidly gives me the actual hateful cost of the clothes, which is £59.95.
Resources
Here's a few resources I've establish for instruction this topic:
- Teachitmaths.co.uk has a lovely worksheet for helping pupils empathise the comport upon of coding. Just beware of the fault inward the extension questions - both information sets should accept 6 values, non five.
- Schoolworkout.co.uk has this sorting activity and this worksheet.
- Phildb on tes.co.uk has written this worksheet.