we are going to be looking at ordering
integers
both positive and negative numbers
let's start by ordering the numbers
positive two and positive nine
we can use a number line to help us
here are positive 2 and positive 9 on a
number line
if we move from left to right on the
number line the numbers get bigger
positive 9 is further to the right than
positive two
so we can say that positive nine is
greater than positive two
there is a special way we write this in
maths
to help you remember this we are going
to use a greedy crocodile
the greedy crocodile always wants to eat
the bigger number
he opens his jaws wide to eat it
this shape of his jaws is the same as
the symbol we use
this symbol is called an inequality sign
this mathematical expression
means that positive 9 is greater than
positive 2.
if we read the number line from right to
left or going down the number line the
numbers get smaller
positive 2 is further to the left than
positive nine
so we can say that positive two is
smaller than positive nine
again we have a special way to write
this and again we are going to use the
greedy crocodile
he still wants to eat the bigger number
and the shape of his jaws gives us the
shape of the less than symbol
this says that positive 2 is less than
positive nine
now let's compare some negative numbers
negative five and negative eight
negative five is further to the right
than negative eight
so we can say that negative five is
greater than negative eight
let's use the crocodile to help us
remember the symbol
the greedy crocodile eats the bigger
number so this says negative five is
greater than negative eight
negative eight is further to the left on
the number line than negative five
so we can say that negative eight is
less than negative five
the greedy crocodile still wants to eat
the bigger number
so we can write this out like this
one more set of numbers for us to
compare
positive three and negative four
here they are on the number line
positive three is further to the right
than negative four
so we can say that positive three is
greater than negative four
the greedy crocodile will help us write
this out in a mathematical way
the greedy crocodile eats the bigger
number
this gives us the shape of the symbol
this says positive three is greater than
negative four
negative four is further to the left
than positive three
so we can say that negative four
is less than positive three
our greedy crocodile wants to eat the
bigger number
giving us the shape of the symbol we
need to use
this says
negative four is less than positive
three
we can use these inequality signs when
we arrange things in order
let's put these numbers in order
we know all negative numbers are less
than zero
and all positive numbers are greater
than zero
so we put zero in the middle first
now we can group all the positive
numbers together
and all the negative numbers together
we want to arrange in ascending order
so we want the number furthest to the
left
on the number line
this is
negative 10
as we move up the number line we get to
negative 5
then negative four
and negative two
all the positive numbers are greater
than zero
and as we go up the number line we would
get positive three first
then positive seven
and finally positive nine
these numbers are now in ascending order
but we can put inequalities between them
like this
remember to think of the greedy
crocodile eating the bigger number
here are some more numbers that we are
going to arrange in descending order
again we first split them into positive
and negative
this time we want the number furthest to
the right on the number line first the
most positive number which is positive
92
as we go down the number line the next
number we would reach is positive 38
as we go down past 0
we would start to get more negative
negative 28 would come first
then negative 43
and finally negative 100
these numbers are now in descending
order
again we can use inequalities between
each number
you