Coordinates on Maps
Maps often use a grid or system of coordinates to fix the position of a place on a map.
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On this map the approximate locations of the three places can be given as:
Northtown B10
Landville A11
Hare's Rocks B11
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Coordinates in Mathematics
In mathematics, the position of points can be given much more accurately.
Two number lines are drawn at right angles. This grid is called a number plane or a Cartesian graph.
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The horizontal axis is called the x-axis.
The vertical axis is called the y-axis.
The x-axis and the y-axis cross at the origin, O
A point is given by a pair of coordinates (x, y).
Coordinates are sometimes called ordered pairs.
The first number is the position along the x-axis. The second number is the position along the y-axis.
e.g. Point A is given by (3, 5)
Point B is given by (-3, -2)
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Sequences 
In mathematics, numbers are often arranged in a sequence. Often a sequence follows a rule or pattern. Each number in a sequence is called a term.
Sequence − Example One Some sequences are obvious: 2, 4, 6, 8, 10... This is the sequence of EVEN numbers. To continue writing the sequence simply keep adding 2.
Comparing this sequence to the set of counting numbers N = {1, 2, 3, 4..}
n
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1
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2
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3
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4
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5
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...
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y
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2
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4
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6
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8
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10
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...
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The sequence can be shown as a graph:

The formula for this pattern is 2n. The next term, the sixth, would be 2 × 6 = 12
Sequence − Example Two The sequence 1, 4, 7, 10, 13... is the sequence starting at 1 with three added each time. To continue writing the sequence simply keep adding 3.
Comparing this sequence to the set of counting numbers {1, 2, 3, 4..}
1
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2
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3
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4
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5
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...
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1
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4
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7
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10
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13
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...
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The sequence can be shown as a graph:

The formula for this pattern is 3n − 2 . The next term, the sixth, would be 3 × 6 − 2 =16
Sequence − Example Three Another kind of sequence is1, 4, 9, 16, 25... This is the sequence of square numbers. To continue writing the sequence keep squaring the whole numbers, 62 = 36 etc.
Comparing this sequence to the set of counting numbers {1, 2, 3, 4..}
1
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2
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3
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4
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5
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...
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1
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4
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9
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16
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25
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...
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The sequence can be shown as a graph:

The formula for this pattern is n2 . The next term, the sixth, would be n2= 36
Patterns
Sequences can also be of diagrams or geometric patterns. For example:

The next pattern in this sequence would be a 6×6 square with 16 yellow squares in the middle surrounded by a border of pink squares.
Graphs
As well as graphs for sequences, there are many other types of graphs. All graphs must have certain features:
- A title
- Labelled axis indicating units used
- Even scales
Line Graphs
Line graphs show how quantities are changing. Below are four examples:

This graph shows the water heating up steadily till it boils after 6 minutes.
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Notice the changes in the boy's height as he moves through his teenage years.
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The number of containers changes considerably from month to month.
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Line graphs are often used to show distance and time.
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Other types of graphs such as Cartesian graphs (x-y graphs) and scatter graphs are studied in more detail in later years.
Statistical Graphs
These graphs are detailed in Topic 44.
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