# Whole (natural) numbers

*Natural numbers. Natural series. Integers.*

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Natural numbers
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numbers, which appear as a result of calculus of single subjects:peoples, animals, birds, trees, different wares and so on. Series of natural numbers: 1, 2, 3, 4, 5, … is continued endlessly and is called

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*natural series*
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Integers
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– natural numbers and zero: 0, 1, 2, 3, 4, 5, … . Concept

*"integers"*is expanded in the section "Rational numbers" of the part "Algebra".