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# Number

The following are numbers: 0, 1, 2, 2.5, 12.75, 0.5, 7e6 .

Enter these, and other numbers, in simple sentences with the verbs `+ - *` and `%`.

    2 * 12.75
    25.5

An important rule is that a number does not start with a dot.

    0.5
    0.5

       0.5 + 3
    3.5

       .5
    +---+
    ¦.¦5¦
    +---+

       .5 + 3
    ¦syntax error
    ¦        .5+3

Clearly `.5` is not the same as `0.5`. You don't need to know now what `.5` is, but it is important to understand that a number does not start with a dot.

The `_` (underbar) is infinity and is a number.

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