Kitap 7
DEFINITIONS.
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1
An unit is that by virtue of which each of the things that exist is called one.
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2
A number is a multitude composed of units.
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3
A number is a part of a number, the less of the greater, when it measures the greater;
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4
but parts when it does not measure it.
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5
The greater number is a multiple of the less when it is measured by the less.
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6
An even number is that which is divisible into two equal parts.
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7
An odd number is that which is not divisible into two equal parts, or that which differs by an unit from an even number.
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8
An even-times even number is that which is measured by an even number according to an even number.
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9
An even-times odd number is that which is measured by an even number according to an odd number.
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10
An odd-times odd number is that which is measured by an odd number according to an odd number.
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11
A prime number is that which is measured by an unit alone.
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12
Numbers prime to one another are those which are measured by an unit alone as a common measure.
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13
A composite number is that which is measured by some number.
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14
Numbers composite to one another are those which are measured by some number as a common measure.
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