After studying this course, you should be able to:

• write whole numbers and decimals in place-value columns and compare their sizes

• multiply and divide whole numbers and decimals by 10, 100, 1000 and so on

• indicate given fractions on a diagram and find equivalent fractions for a given fraction

• mark numbers on a number line

• choose appropriate units for a given purpose.

Author(s): The Open University

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Up to now only those points with positive or zero coordinates have been considered. But the system can be made to cope with points involving negative coordinates, such as (âˆ’2, 3) or (âˆ’2, âˆ’3). Just as a number line can be extended to deal with negative numbers, the x-axis and y-axis can be extended to deal with negative coordinates.

Author(s): The Open University

## Activity 16

Write down the coordinates of A and B.

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## Activity 10

This table categorises Tom's activities for the day.

Activity<
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## Activity 7

Tables often give information in percentages. The table below indicates how the size of households in Great Britain changed over a period of nearly 30 years.

Number of people in household1961 (%)1971 (%)1981 (%)1991 (%)
1Author(s): The Open University

## Activity 6

The table below indicates the cooling rate of tea in a teapot.

Time/mins
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Experiments or surveys usually generate a lot of information from which it is possible to draw conclusions. Such information is called data. Data are often presented in newspapers or books.

One convenient way to present data is in a table. For instance, the nutrition panel on the back of a food packet:

### Nutrition Information

Author(s): The Open University

Another way to say â€˜subtract one number from anotherâ€™ is to say â€˜one number minus anotherâ€™. And the standard sign to show this is a minus sign, which looks like this â€˜â€“â€™. The expressions â€˜take awayâ€™ or â€˜take fromâ€™ are also used to mean subtract or minus.

So the following expressions all mean the same thing:

• What do I get if I subtract 2 from 3?
• What do I get if I take 2 from 3?
• What is 3 take away 2?

• Author(s): The Open University

Now that youâ€™ve learned the principles of doing division on paper, you may want to practise your new skills. If so, go to the Dividing decimals page of the math.com website and follow the instructions. You will need a pen and paper to carry out each calculation. You can then enter your answer on the website to check if it is correct.

Author(s): The Open University

Doing division when decimal numbers are involved is the same as doing divisions involving whole numbers, with a few extra steps to take care of the decimal point.

Either the number you are dividing into or the number you are dividing by, or both of them, may be a whole number or a decimal number. So, for example, you might want to do the following divisions:

• Example 1: 49.26457 Ã· 8
• Example 2: 2.601 Ã· 1.22
• Example 3: 678 Ã· 27.356
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In the previous sections you saw how to divide a big number by a small number up to 10. Things get harder if you want to do a division where both the numbers are big. This kind of calculation is called long division, probably because you write the steps of the calculation out on paper in a long sequence.

The principle of doing long division is the same as when you divide by a number up to 10. The only difference is that, because the numbers involved in long division are usually too big
Author(s): The Open University

A decimal number is a different way of representing numbers smaller than one. You put them after a full stop (the decimal point), for instance 0.5. The first digit after the decimal point represents tenths. If you sliced a cake into 10 slices, each slice would be a tenth of the cake. So 0.5 is the same as saying 5 tenths, and can be written Author(s): The Open University

An important thing to remember about division is that it has different rules from multiplication.

For example when you multiply two numbers together, it doesnâ€™t matter what order you multiply them in. So 8 x 4 is exactly the same as 4 x 8. The result is 32 in both cases.

But in division, order matters. So 8 Ã· 4 is different from 4 Ã· 8.

The answer to the first is 2. If you multiply 4 by 2 you get 8.

But the answer to the second is 0.5 (a half). If you multiply 8 by
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In this section, you have learned about appropriate ways of interpreting data in tables. By working through examples, you have seen how it can be useful to calculate appropriate proportions and ratios, and to present some of the data in graphical form. Guidelines for the choice of graphics have been given. When the data in a table are in the form of counts, you have seen that it can be useful to calculate the counts in a particular row or column as proportions (usually in the form of percenta
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## Activity 7 Health care personnel in Thailand: calculating percentages

Would it be helpful, in considering possible changes in the way health care personnel are divided into the five categories listed, to recalculate th
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In Section 2, the main concern was with producing a table of data, for others to read, that communicates clearly the important patterns or messages in the data. In this section, the focus changes slightly. Your role will be that of the reader or user of the data in a table, and you will learn about approaches that make it easier for you to extract information from a table. However, manipulating tabular data into a form that makes it clearer to others will also, very often, make it clearer to
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