# Compound Measures

Scheme of work: GCSE Foundation: Year 10: Term 4: Compound Measures

#### Prerequisite Knowledge

• know and apply formulae to calculate:
• rectangles
• rectilinear composite shapes
• area of triangles
• volume of cuboids
• use standard units of measure and related concepts (length, area, volume/capacity, mass, time, money, etc.)

#### Success Criteria

• use standard units of mass, length, time, money and other measures (including standard compound measures) using decimal quantities where appropriate
• round numbers and measures to an appropriate degree of accuracy (e.g. to a specified number of decimal places or significant figures)
• change freely between related standard units (e.g. time, length, area, volume/capacity, mass) and compound units (e.g. speed, rates of pay, prices, density, pressure) in numerical and algebraic contexts
• use compound units such as speed, rates of pay, unit pricing, density and pressure

#### Key Concepts

• It is useful to calculate compound measures through the unitary method where ratios are in form 1 : n.
• Distance â€“ Time graphs can be extended to Speed-Time/Acceleration-Time graphs.
• Use algebraic techniques to manipulate the various formulae so that other measures can also be found.

#### Common Misconceptions

• Density, pressure and time do not have to have fixed units. For instance, a speed can be m/s or mph; density can be g/cm3 or kg/3.
• Students often have difficulty remembering which measure to divide by. The speed, pressure and density triangles are helpful to recall the relationship between the various measures.

## Compound Measures Resources

### Mr Mathematics Blog

#### Problem-Solving with Angles in Polygons

How to teach problem solving with angles in polygons through scaffolding.

#### The Sum to Infinity of Geometric Series – A-Level Maths Tutorial

Explore geometric series in our A-Level Maths tutorial. Perfect for students/teachers, with resources to download at mr-mathematics.com.

#### Sequences and Series

Edexcel A-Level Mathematics Year 2: Pure 2: Algebraic Methods