The same rules about the order of calculations apply to decimals as apply to whole numbers.

## Calculations are performed in the following order:

Brackets;

Powers (e.g. squaring or cubing a number);

Division and Multiplication (performed in the order written, left to
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## Activity 30

Carry out the following calculations, without your calculator.

• (a) 3 Ã— (60 + 70).

• (b) (3 Ã— 60) + 70.

• (c) (70 âˆ’ 60) Ã· 5.

• Author(s): The Open University

There are two very famous formulas for circles:

circumference of a circleÂ =Â Author(s): The Open University

You may like to add the area formulas in this section to your notes for future reference.

The simplest areas to find are those of rectangles. The area of a rectangle is its length multiplied by its breadth. Sometimes the dimensions of a rectangle are referred to as the base and the height, instead of the length and the breadth. The area is then expressed as the base multiplied by the height.

â€ƒ

## Study another free course

There are more thanÂ 800 coursesÂ on OpenLearnÂ for you to
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A fundamental concept in mathematics is that of a function.

Consider, for example, the function f defined by

This is an example of a real function, because it associates with a given real number
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School mathematics curricula often focus on lists of content objectives in areas like number, arithmetic, statistics, measurement, geometry, trigonometry, and algebra. A typical list of content objectives might contain over one hundred objectives to be introduced or revisited and learned each year. These can be seen as hierarchical in nature but many textbooks do not attempt to organise the objectives in ways that enable the bigger underpinning ideas to become apparent to the pupils. In addit
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## Question 5

Information on the different albedos of various types of surface was given in Author(s): The Open University

## SAQ 9

Look back at Figure 7. In this schematic representation, what is the fate of incoming solar radiation?

It is either reflected back to spa
Author(s): The Open University

The atmosphere is not a simple, uniform slab of absorbing material. On the contrary, it gets progressively 'thinner' or less dense with increasing altitude (height above mean sea level); i.e. the total number of molecules in a given volume of air is lower, and so is the pressure. About 80% of the total mass of the atmosphere is within some 10 km of the surface; 99.9% lies below 50 km.

The important corollary is that the key greenhouse gas molecules (H2O and CO2
Author(s): The Open University

Capra, F. (1996) The Web of Life. Used by permission of Doubleday, a division of Random House, Inc., and, in the UK, reprinted by permission of HarperCollins Publishers Ltd.
Capra, F. (2002) The Hidden Connections: Integrating the Biological, Cognitive, and Social Dimension of Life into a Science of Sustainability. Used by permission of Doubleday, a division of Random House, Inc., and, in the UK, reprint
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The question arising from the previous two imperatives of systems thinking â€“ dealing with holism and engaging with multiple perspectives â€“ is how we might develop frameworks that deal responsibly with our inevitable limitations on being holistically comprehensive and epistemologically â€˜multiverseâ€™. Ulrich reminds us that a â€˜systems approachâ€™ to environmental responsibility is perhaps not quite the panacea that it so often mistakenly promises to be. Take, for example, the â€˜ecosys
Author(s): The Open University

Climate change is a natural process of warming and cooling that has occurred all through the Earth's history. Throughout geological time there have been â€˜hot-houseâ€™ periods and ice ages. In order to understand the current situation, it is necessary to have some sense of context and perspective, from historical and geological time-scales. The document below shows a chart showing a generalised temperature history of the Earth.

Click on the link below to see the chart

Author(s): The Open University

We are also guilty of importing exotic species, some of which, like the rhododendron (imported from Asia to Europe), have run riot in the absence of natural predators or primary consumers, and so have tended to out-compete native plants. Sometimes introductions have been accidental; rats and many disease-causing organisms have spread around the world via relatively modern transportation such as sailing ships. However, deliberate introductions, such as the rhododendron, have been made with wor
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A key objective of developing countries in trade liberalisation negotiations is access for their exports to the markets of developed countries. However, the rules have been played out by developed countries in ways that block the hoped-for rise in exports.

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The Ministerial Declaration adopted by WTO members at Doha on 14 November 2001 fails to address the most pressing needs either of the poorest countries or of the world's most vulnerable communities. This means that the people who most need a share in global prosperity are still those least likely to obtain it.

(A joint statement by Actionaid, CAFOD, Christian Aid, Oxfam, Save the Children and five other charities a
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Energy policy and climate change
The 2009 United Nations Climate Change Conference in Copenhagen presents a new focus for international debate and decisions about energy and its use. What are the countries of Western Europe and Scandinavia doing to promote sustainable energy production? Just how different will the future energy map of Europe look? And is energy policy principally a scientific issue or a political one? This album contains a series of films exploring energy policy in various countries around Europe in 2006, frame
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Structural Integrity: Materials Testing
How is safety built into the design of new structures? What sort of tests are used to ascertain the safety of proposed designs? Structural integrity, the study of the safe design and assessment of materials and structures under load, has become crucial in engineering design. Concepts within stress analysis have wide applicability, as there are very few manufactured components and products that do not experience any loading during their life. The tracks on this album demonstrate a selection of
Author(s): The OpenLearn team

Water Treatment
Do you think about where your water comes from? In the UK each of us uses an average of about 150 litres of water per day! The seven video tracks in this album consider issues of demand and quality in water supply as well as treatment processes. They give information on methods of minimising waste, emergency water treatment and effluent control. This material forms part of T308 Environmental monitoring, modelling and control.Author(s): The OpenLearn team

Waste Management
How much do you think about what you throw away? A waste management cycle is essential for a sustainable future. This album considers the policy and legislation that is driving waste management processes across the EU. By modelling the overall environmental impacts of solid waste disposal methods, the UK government has now created a hierarchy of waste and local management strategies. The 12 video tracks in this album offer an in depth look at each of these processes, concentrating on waste coll
Author(s): The OpenLearn team