Conversions (Grade 11 NSC Matric Mathematical Literacy): Revision Notes
Conversions
What are conversions?
Conversions involve changing measurements from one system to another. This is essential for solving real-world problems where different measurement systems are used together.
As a Grade 11 Mathematical Literacy student, you need to master conversions between:
- Imperial and metric systems (e.g., kilograms to pounds)
- Temperature scales (Celsius to Fahrenheit and vice versa)
- Different units within the same system (e.g., grams to millilitres)
Mastering these conversion skills is essential for success in Mathematical Literacy, as conversion problems frequently appear in exams and real-world applications.
Types of conversions
Imperial and metric system conversions
These conversions help you work between the measurement systems used in different countries. The conversion factor will always be provided in exam questions.
Key principle: Use the rates method to solve conversion problems.
Method:
- Set up a proportion using the given conversion factor
- Cross-multiply to find the unknown value
- Always check if rounding is required
Temperature conversions
Temperature conversions use specific conversion formulas that you must memorise.
Key Temperature Formulas (Must Memorise):
- Celsius to Fahrenheit:
- Fahrenheit to Celsius:
Method: Substitute the known temperature into the appropriate formula and calculate step by step.
Worked examples
Worked Example 1: Imperial to Metric Conversion
Problem: Convert 78 kg to pounds, given that 1 kg ≈ 2,206 pounds.
Solution: Using the rates method: If 1 kg ≈ 2,206 pounds, then 78 kg = 2,206 pounds × 78
(rounded to 1 decimal place)
Worked Example 2: Metric to Imperial Conversion
Problem: Convert 150 pounds to kilograms, given that 1 kg ≈ 2,206 pounds.
Solution: Using the rates method: If 1 kg ≈ 2,206 pounds, then 1 pound ≈ 1 kg ÷ 2,206
Worked Example 3: Temperature Conversion
Problem: Convert 35°C to degrees Fahrenheit.
Solution: Using the formula:
Therefore, 35°C = 95°F
Exam tips
When approaching conversion problems in exams, it's crucial to follow a systematic approach. Always check what conversion factor is given in the question, as this will be your starting point for any calculation.
Essential Exam Strategy Points:
- Show all working using the rates method or substitution into formulas
- Round appropriately - the question will specify how many decimal places
- Include units in your final answer
- Double-check by working backwards if you have time
Common exam traps
Understanding where students commonly make mistakes can help you avoid these pitfalls and achieve better results in your exams.
Critical Mistakes to Avoid:
- Forgetting to include the +32° or -32° in temperature conversions
- Using the wrong conversion formula (mixing up Celsius to Fahrenheit with Fahrenheit to Celsius)
- Not rounding to the specified number of decimal places
- Mixing up which number to multiply or divide by in rates method
Remember!
Key Points to Remember:
- Conversion factors are always provided in exam questions - you don't need to memorise them
- Temperature conversion formulas must be memorised: and
- Use the rates method for imperial/metric conversions by setting up proportions
- Always show your working step by step for full marks
- Check that your answer makes sense - 35°C should be quite hot in Fahrenheit (95°F)