The basic SI unit for mass is the kilogram, symbol kg

The tonne (t) which is equivalent to 1000 kg and is a metric unit is often used alongside the SI units.

The animation below illustrates how to convert between the most commonly used units of mass, the metric tonnne (t); the kilogram (kg); the gram (g); the milligram (mg) and the microgram (Î¼g).

Author(s): The Open University

## Activity 15

Suggest appropriate units for each of the following:

• (a) the age of the kitten when it is weaned;

• (b) the distance between one train station and the
Author(s): The Open University

## Activity 9

The diagram below shows an oatmeal cake marked into 12 equal portions. I want to give my sister a third of the cake. Where could I cut the cake, and what would be left over?

Author(s): The Open University

## Activity 6

What is 370.76 grams in kilograms? There are 1000 grams in a kilogram.

370.76 Ã· 1000 = 0.370 76.

So 370.76 g = 0.370
Author(s): The Open University

## Activity 2

Write each of the following three numbers in numerals and then place them in ascending order:

• eight hundred and eight thousand

• two million and twenty
Author(s): The Open University

The Consumer Prices Index (CPI) and the Retail Prices Index (RPI) are published each month by the UK Office for National Statistics. These are the main measures used in the UK to record changes in the level of the prices most people pay for the goods and services they buy. The RPI is intended to reflect the average spending pattern of the great majority of private households. Only two classes of private households are excluded, on the grounds that their spending patterns differ greatly from t
Author(s): The Open University

The content acknowledged below is Proprietary (see terms and conditions) and is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence

Grateful acknowledgement is made to the following sources for permission to reproduce material in this course:<
Author(s): The Open University

Except for third party materials and otherwise stated (see terms and conditions), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence.

The material acknowledged below is Proprietary and used under licence (not
Author(s): The Open University

The main aim of this section is to show an application of distance-time graphs in the operation of a railway service.

You will need graph paper for this section.

This section uses the video â€˜Single track mindersâ€™ to illustrate how distance-time graphs are drawn and interpreted by the timetable planners of a small railway company, and shows the role of this graphical technique in planning a flexible service. Graphical representations of journeys have been used for over a centur
Author(s): The Open University

Time-series graphs are popular with newspapers for suggesting and comparing trends. But showing how a single quantity varies with time is not the same as showing how two quantities vary, and then suggesting a link between them.

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Mathematicians use some special terms to talk about graphs. Understanding and feeling confident with this graphical language is as much a part of mathematics as doing calculations, or working with formulas. By convention, the horizontal axis of a graph â€“ the one running across the page from left to right â€“ is often called the â€˜x-axisâ€™, and the vertical axis â€“ the one running up the page â€“ is called the â€˜y-axisâ€™, as in Author(s): The Open University

So time-series graphs must be read with care. Adopt a questioning attitude when you are faced with a graph. Look carefully at the vertical axis to see just what the range of variation is, and at the horizontal axis to see what time intervals have been chosen. Ask yourself about the significance of this choice â€“ what might be going on between each plotted point?

You might question whether the plotted variation is significant or whether it is the result of expected fluctuations. What ab
Author(s): The Open University

Grateful acknowledgement is made to the following sources for permission to reproduce material in this course:

The content is taken from an activity written by Marion Hall for students taking courses in Health and Social Care, in particular those studying K101 An Introduction to Health and Social Care. The original activity is one of a set of skills activities made available to all HSC students via the HSC Resource Bank.

Except for third party materials and otherwise stated (see
Author(s): The Open University

Subtracting whole numbers such as 52 from 375 is fairly straightforward. Subtracting decimal numbers such as 6.892 from 223.6 uses the same process but with one extra step â€“ you have to line the decimal points up first.

Rather than arranging your two numbers so that they line up on the right-hand side, you need to line up the decimal points, regardless of how many numbers there are after the decimal point. In the example below, the top number has one number after the decimal point. It
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The example of 25546 divided by 53 is suitable for long division. First write the calculation down on paper in the same way you did before.

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If the number you are dividing by does not go exactly (with no remainder) into the digit you are dividing into, you need to do something called carrying.

Say you want to divide 952 by 7. The process is basically the same as in the previous section. First write it down on paper. Then, to do the calculation, you take each digit from the number being divided in turn, starting with the one on the far left, and see how many times the dividing number, 7 in this case, goes into it. The calcula
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The USA workforce data in Table 2 were usefully summarised in Figure 6, w
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Course image: JÃ¶rg Reuter in Flickr made available under Creative Commons Attribution-NonCommercial-ShareAlike 2.0 Licence.

Grateful acknowledgement is made to the following sources for permission to reproduce material in this course:

The content acknowled
Author(s): The Open University

You should not expect always to be able to read a problem and then just write down the answer. When you are faced with a written mathematical question or problem to solve, read it carefully. It is important that you get to grips with the question in two ways: first, that you absorb the information given; and second, that you find out what the question is really asking. Your solution will link the two. This method can be summarised by the following questions.

Author(s): The Open University

## Activity 2

Here is a poor example of mathematical writing, although the final answer is correct. Rewrite it, correcting the layout and the mathematical punctuation.

Author(s): The Open University