1. Session 19 – Measures
GCSE Maths

2. Length - cm, metres, km, inch, feet, miles
Mass (weight) - kg, pounds, ounces
Capacity (volume) – litres, gallons cm3

3. Metric units Kilo… Centi… Milli….
When converting between metric unit we multiply or divide by 10, 100 or 1000

4. Converting area and volume
How many cm3 in 1m3?
Ex31.1 Q 7, 8, 11, 16 and 19

5. Estimation using ‘common sense’
The degree of accuracy is determined by what we ae measuring.
Heights of mountains are not measured to the nearest mm, or even nearest cm.
Time in the Olympics is recorded to 1/100 of a second
EX31.2 Q 1 and 6 through discussion

6. Imperial measures 1 foot = 12 inch 1 yard = 3 feet 1 pound = 16 ounces
14 pounds = 1 stone
1 gallon = 8 pints

7. Conversions to remember (approximate)
1 mile = 1.6 km (8/5 = 1.6) (km is shorter)
1 inch = 2.54 cm
1 foot = 30 cm (think of a ruler)
1kg = 2.2 pounds
1 pint = 568ml or 1l = 1.75 pints
1 gallon = 4.5l
Ex31.3 – 10 mins

8. Discrete and continuous data
Continuous data is measured and can take any value (it depends on the degree of accuracy you measure to)
Discrete data only takes certain values. eg the number of people or a shoe size or ice skating score

9. Upper and lower bounds
If continuous measure (c) is recorded to the nearest x then the limits of possible values for c are:
C± 𝑥
For example
18cm (recorded to the nearest cm)
Lies between 17.5cm and 18.5cm
Although it could never be 18.5cm, but it could be cm

10. Calculating using upper and lower bounds
Example page 333
Try a few from 31.5

11. Dimensions Length, area, volume how many dimensions
If a b and c all represent length, they can all be replaced by L
Length – 1 dimension = L
Area dimensions = L2
Volume dimensions = L3
Any formula that cannot be simplified down to one of these can be called ‘inconsistent’ as it does not represent length, area or volume (see example d page 335)

12. Any time at the end go through BKSB
Encourage everyone to begin their revision of topics covered

13. Homework Use BKSB to revise topics
Produce a revision page for the geometry ‘what you need to knows’
Including 2D shapes, 3D shapes and circles