2b. neg and pos
TRANSCRIPT
Positive and Negative Numbers
Created by Richard Bull
Definition
• Positive number – a number greater than zero.
0 1 2 3 4 5 6
Definition
• Negative number – a number less than zero.
0 1 2 3 4 5 6-1-2-3-4-5-6
Negative Numbers Are Used to Measure Temperature
Negative Numbers Are Used to Show Debt
If you get a loan from the bank for £5,000.If you were to look at your bank balance it would show -£5,000.
Negative Numbers Are Used to Measure Under Sea Level
0102030
-10-20-30-40-50
Hint
• If you don’t see a negative or positive sign in front of a number it is positive.
9+
Integer Addition RulesRule #1•If the signs are the same, pretend the signs aren’t there and add them.
-9 + -5 = 14Rule #2•Ask which absolute number is bigger•now remember what sign it was, this is the sign for your answer
-
Solve the Problems• -3 + -5 =• 4 + 7 =• -6 + -7 = • 5 + 9 =• -9 + -9 =
-8
-18 14-1311
Integer Addition RulesRule #2•If the signs are different,
3 + -5 =pretend the signs aren’t there and subtract the smaller absolute number from the larger absolute number
5 - 3 = 2 Now look back at the original question and use the sign of the biggest absolute number for your answer
3 + -5 =
-
Solve These Problems•3 + -5 =• -4 + 7 =• (+3) + (-4) =• -6 + 7 = •5 + -9 =• -9 + 9 =
-25 – 3 = 2
0 -41
-13
9 – 9 = 0 9 – 5 = 47 – 6 = 1
4 – 3 = 17 – 4 = 3
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6
When the number is positive countto the right.
When the number is negative countto the left.
+-
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6+
-
+3 + -5 = -2
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6+
-
+6 + -4 = +2
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6+
-
+3 + -7 = -4
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6-
+
-3 + +7 = +4
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6-
+
-5 + +3 = +4
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6-
+
-2 + +8 = +6
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6-
+
-5 + +2 = -3
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6-
-
-4 + -2 = -6
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6-
-
-2 + -3 = -5
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6-
-
-1 + -4 = -5
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6-
-
-4 + -1 = -5
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6+
+
4 + 1 = 5
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6+
+
3 + 2 = 5
One Way to Add Integers Is With a Number Line
0 1 2 3 4 5 6-1-2-3-4-5-6+
+
1 + 5 = 6
Add integers with same signs:
Add the numbers and keep the sign
a)3 + 2 = 5 b) -4 + (-6) = -10
Add integers with different signs:
Subtract the (absolute values) and keep the sign of the sign of the absolute value
a) -7 + 4 = -3 b) 1 + (-9) = -8
Created by Richard Bull