Calculating a Quantity
Calculating a Quantity
Measure Units
- Understand that quantities are presented in specific units of measurements.
- Familiarize yourself with both the imperial system (inches, feet, yards, miles, ounces, pounds, stones, gallons) and the metric system (metres, litres, grams).
- Ensure that you can convert between different units. For instance, 1 kilometre equals 1000 metres, 1 pound equals 16 ounces.
Basic Calculation
- Be able to perform basic arithmetic operations, including addition, subtraction, multiplication and division.
- Be capable of using a formula to calculate a specific quantity. E.g., to calculate area of a square, use side x side.
- Understand how to calculate percentages for quantifiable values in a given scenario, such as discounts or increases.
Use of Proportions
- Grasp that proportions can be used to calculate quantities.
- Know that a proportion states that two ratios or fractions are equivalent. For instance, if 20 apples cost 5 pounds, then 40 apples cost 10 pounds.
- Understand that proportional relationships can constitute a key part of calculations involving quantities.
Scientific Notations
- Understand scientific notations are used to express very large or very small quantities.
- For instance, 4.5 x 10^7 represents a large quantity, while 5.2 x 10^-3 represents a small quantity.
Use of Estimation
- Recognize that estimation can be used when an exact figure is not necessary.
- When estimating, it’s important to judge whether the answer seems reasonable.
- Bear in mind that estimation is often used to check the plausibility of a calculated answer.
Errors and Accuracy
- Realise that calculations involving measurements are subject to errors.
- Become familiar with the concept of accuracy and know how to express a given measurement to the required degree of accuracy.
- Be conscious of the differences between absolute, relative, and percentage errors, and know how to calculate each type.