Transcript Integers - Oberlin USD 294

Integers
What????
Integers
An integer is a whole number (not
a fraction) that can be positive,
negative, or zero. Therefore, the
numbers 10, 0, -25, and 5,148 are
all integers.
Integers
Know the signs
+ Positive
(If it has NO sign, it is POSITIVE.)
- Negative
(AKA: opposite of)
Integers
In order from least to greatest
-25, -5, -2, 0, 10, 51, 78
Integers
Correct order from least to greatest?
5, -1, -5, 1, 11, -11, 0
The correct order is…
-11, -5, -1, 0, 1, 5, 11
Adding
Think MONEY!!
Adding
Signs the same??
Add and keep the signs
+2 + + 3 = +
5
-2 + - 3 = 5
Think MONEY!!
Sue has $2. Nancy gives her
$3. Has much does Sue have
now?
+
2 + +3 = +5
Think MONEY!!
Sue owes $2. She needs to pay
Miss Dixson $3. How much
does Sue owe now?
-
2 + -3 = -5
Adding
Signs different??
Actually subtract
Keep the sign of the
“larger” number
Adding
Signs different??
+ 2 + -3 = -1
(3 - 2 =1 Use the sign
of the 3 because 3 is
larger than 2)
Adding
Signs different??
Sue wrote a check for $2. Billy
gave Sue $3. How much does
Sue have now?
-2 + + 3 = + 1
Remember When
Adding
Think MONEY!!
Subtracting
Do you already know how
add integers?
YES!
Subtracting
If you know how to add,
you can also subtract.
Cool!
Subtracting
Change the sign of the
2nd integer and add
+2
-
-3
=
+5
That’s it! Easy, huh?
Subtracting
Change the sign of the
2nd integer and add
ALWAYS the 2nd integer
Subtracting
Change the sign of the 2nd
integer and add (Now it is just like
what we’ve done in the past.)
+2
-
-3
=
+5
Multiplying
If the signs are the same, the
product will be positive.
+x+=+
-x-=+
+2 x +3 = +6
-2 x -3 = +6
Multiplying
If the signs are different, the
product will be negative.
+x-=-
-x+=+2 x -3 = -6
-2 x +3 = -6
Dividing
If the signs are the same, the
result will be positive.
+÷+=+
-÷-=+
+6 ÷ +3 = +2
-6 ÷ -2 = +3
Dividing
If the signs are different, the result
will be negative.
+÷-=-
-÷+=+6 ÷ -3 = -2
-6 ÷ +3 = -2
Integers
Aren’t they
fun????