Summary
Measures and accuracy involve using standard units, estimation, and rounding to ensure calculations are precise and meaningful.
- Standard Units — basic units used for measuring quantities like mass, length, and time. Example: 1 hour = 60 minutes = 3600 seconds.
- Currency Conversion — converting one currency to another using exchange rates. Example: ₤225 converted to euros at a rate of ₤1 = €1.62 results in €364.5.
- Speed Calculation — speed is calculated by dividing distance by time. Example: A car traveling 400m in 20 seconds has a speed of 20 m/s.
- Approximation and Estimation — simplifying calculations by rounding numbers to make them easier to work with. Example: 2.1 x 6.8 is approximately 14 when rounded to 2 x 7.
- Rounding Numbers — adjusting numbers to a specified degree of accuracy, such as to the nearest integer or decimal place. Example: 152.836 rounded to one decimal place is 152.8.
Exam Tips
Key Definitions to Remember
- Standard units of measurement
- Currency conversion using exchange rates
- Speed as distance divided by time
- Rounding to significant figures and decimal places
Common Confusions
- Mixing up units of time, such as minutes and seconds
- Incorrectly applying exchange rates in currency conversion
- Misunderstanding the difference between significant figures and decimal places
Typical Exam Questions
- How do you convert 10 days and 9 hours into minutes? Multiply days by 1440 and hours by 60, then add.
- What is the speed of a car that travels 400m in 20 seconds? Speed = 400m / 20s = 20 m/s.
- Estimate the result of 906 + 397. Round to 900 + 400 = 1300.
What Examiners Usually Test
- Ability to use and convert standard units
- Skill in estimating and approximating calculations
- Proficiency in rounding numbers to various degrees of accuracy