The set of the natural numbers, order and representation
Write, using the symbols $ < $ and $ > $, the following sentences:
a) $5$ is greater than $3$
b) $2$ is less than $7$
c) $4$ is greater than $5$
a) $5$ is greater than $3$ is the same as $5 > 3$.
b) $2$ is less than $7$ is the same as $2 < 7$.
c) We can write $4 > 5$, but it's not true because $4$ isn't greater than $5$.
a) $5 > 3$
b) $2 < 7$
c) $4$ is greater than $5$ can be translated to $4 > 5$, which is false.
Which of these numbers are natural?
a) $2.3$
b) $80$
c) $2$
d) $-12$.
a) Can we say: "I have $2.3$ brothers?"" No, perhaps we have two brothers, perhaps three, but we can nothave $2.3$.
b) In this case you can say, for example: "In this field there are $80$ sheep." Therefore, it is a natural number.
c) As in the previous case, it can be used to count things, "My brother is two years old." That is to say, it is also a natural number.
d) This is not for counting objects: "Tomorrow $-12$ guests will visit us!" is not correct.
$2.3$ is not a natural number.
$80$ is a natural number.
$2$ is a natural number.
$-12$ is not a natural number.