Download Subtracting negative numbers 28OCT

Starter Questions
1. Calculate 85% of 160
2. Calculate
a) -2 + 6
b) -3 – 5
c) 6 + (-4)
3. Describe how you would express ⅝ as a percentage.
4. Bill and his 6 friends go out for a meal.
The bill comes to £86.59
They decide to split the bill equally.
How much should each person pay?
Integers
Learning Intentions
To understand how to subtract
negative numbers
Integers
We can use a number line to help us add positive and
negative integers.
–7 + 3 == -4
-7
-4
To add a positive integer we move forwards up the
number line.
Integers
We can use a number line to help us add positive and
negative integers.
2 - 5 == -3
-3
2
To subtract a positive integer we move backwards
down the number line.
Integers
We can use a number line to help us add positive and
negative integers.
–3 + (–4) = –7
-7
-3
To add a negative integer we move backwards down the
number line.
–3 + –4
is the same as
–3 – 4
Integers
We can use a number line to help us subtract positive
and negative integers.
-4 – (-5) = 1
-4
1
To subtract a negative integer we move forward up the
number line.
–4 – (–5) is the same as
–4 + 5
Integers
We can use a number line to help us subtract positive
and negative integers.
–4 – (–7) = 3
-4
3
To subtract a negative integers we move forwards up
the number line.
–4 – (–7) is the same as
–4 + 7
Integers
Now try Ex 9.6
Pg 87 Ch 9
Integers
Learning Intentions
To understand how to subtract
negative numbers