Summary
Understanding measures and accuracy involves using standard units, estimating calculations, and rounding numbers to an appropriate degree of accuracy.
- Standard Units — basic units used for measuring quantities like mass, length, and time. Example: 1 hour = 60 minutes = 3600 seconds
- Currency Conversion — using exchange rates to convert one currency to another. Example: ₤225 converted to euros at ₤1 = €1.62 is €364.5
- Speed — calculated as distance divided by time. Example: A car traveling 400m in 20 seconds has a speed of 20 m/s
- Estimation — approximating calculations by rounding numbers to make them simpler. Example: 2.1 x 6.8 is approximately 2 x 7 = 14
- Rounding — simplifying numbers while maintaining their approximate value. Example: 152.836 rounded to the nearest integer is 153
Exam Tips
Key Definitions to Remember
- Standard units of measurement
- Currency conversion using exchange rates
- Formula for speed: Distance/Time
- Rounding to significant figures and decimal places
Common Confusions
- Mixing up units of time, such as seconds and minutes
- Incorrectly applying exchange rates in currency conversion
- Misidentifying significant figures in a number
Typical Exam Questions
- How do you convert 10 days and 9 hours into minutes? Multiply days and hours by their respective conversion factors to get 14,940 minutes
- What is the speed of a car that travels 400m in 20 seconds? Speed = 400m / 20s = 20 m/s
- Estimate the sum of 906 and 397. Round to nearest hundreds: 900 + 400 = 1300
What Examiners Usually Test
- Ability to use and convert between standard units
- Skill in estimating and approximating calculations
- Understanding of rounding techniques and their applications