Negative Numbers
Identify that numbers less than zero are negative
Whole numbers are the numbers 0, 1, 2, 3, 4, 5, etc…
Integers are the whole numbers and their negatives …-4, -3, -2, -1, 0, 1, 2, 3, 4 …
Positive integers are those integers greater than zero
Negative integers are those integers less than zero.
e.g.
Positive integers:
2, 6, 19, 75, 234, 9 876,
Negative integers: -2, -6, -19, -75, -234, -9 876,
1 000 000
-1 000 000
Appreciate that negative numbers are always smaller than positive numbers
Arrange a list of numbers, positive and negative, on a number line
You can be given a list of integers, positive and negative, and asked to put them in order from
smallest to largest.
The most negative integer should be first in the list (if there are any negatives)
The most positive integer being last in the last (if there are any positives).
e.g.
Put the following integers in order from smallest to largest
23,
56,
-34,
-17,
-88,
45,
-6
Solution
23
-17
-34
-88
-6
So required order is:
-88,
-34,
-17,
-6,
23,
45,
56
45
56
Perform calculations involving negative numbers
We use a number line to help us decide how to add and subtract positive and negative integers.
Adding positive integers – From your starting position move ‘right’ along the number line.
Adding negative integers – Do the opposite of ‘adding positive integers’ so move ‘left’
e.g.
5 + 6 = 11
-10 + 4 = -6
-20 + 42 = 22
-17 + 14 = -3
5 + (-6) = -1
-10 + (-4) = -14
-20 + (-42) = -62
-17 + (-14) = -31
Subtracting positive integers - From your starting position move ‘left’ along the number line.
e.g.
8–5=3
6 – 10 = -4
-3 – 7 = -10
-5 – 18 = -23
Make correct use of the ‘less than’ and ‘greater than’ symbols
<
is the
less than
symbol
>
is the
more than
symbol
These are used to compare the size of positive and negative integers.
The sign always points to the smaller integer.
e.g.
4
<5
-7
<9
6
< 10
-3
< -7
-33
-9
<3
< -32
6>2
19 > 17
6 > -6
16 > -11
12 > - 17
-64 > -67
Hint:
ess than
This graphic helps you remember which way the sign goes.