Download The Equal Sign and Integers

The Equal Sign
and
Integers
What does = mean?
5 + 9 = ____
Some might think the Equal Sign
means “do the operation.” Like – Add
or multiply.
It really means the sides of the
equation are in Balance.
Balance this equation
4+5= 3+?
9=3+?
9=3+6
Now check
9 = 9 This is true! It must be right!
Practice
17 – 5 = 3 + ?
42  6 = 10 - ?
Answers
17 – 5 = 3 + ?
12 = 3 + ?
12 = 3 + 6
check
12 = 12
It checks!
42  6 = 10 - ?
7 = 10 - ?
7 = 10 – 3
7=7
Remember!
Equal means “the same as” or
“Balance” not
do something!
Definition
Positive number – a number greater than
zero.
0 1 2 3 4 5 6
Definition
Negative number – a number less than
zero.
-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6
Definition
– Integers are all the whole
numbers and all of their opposites on
the negative number line including zero.
 Integers
7
opposite
-7
Definition
Value – The size of a number
with or without the negative sign.
 Absolute
The absolute value of
9 or of –9 is 9.
Question?
 Is
that a -3 or minus 3?
Answer - YES!
It is both. A negative 3 is the same as
subtracting a positive 3.
Integer Addition Rules
#1 – If the signs are the same,
pretend the signs aren’t there. Add the
numbers and then put the sign of the
addends in front of your answer.
 Rule
9 + 5 = 14
-9 + -5 = -14
Solve the Problems
+ -5 =
-8
4 + 7 =
11
 (+3) + (+4) =
 -6 + -7 =
-13
5 + 9 =
 -9 + -9 =
14
 -3
-18
7
Integer Addition Rules
#2 – If the signs are different pretend
the signs aren’t there. Subtract the smaller
from the larger one and put the sign of the
one with the larger absolute value in front
of your answer.
 Rule
-9 + +5 =
9 - 5 = 4 Answer = - 4
Larger abs. value
Solve These Problems
+ -5 = 5 – 3 = 2
-4 + 7 = 7 – 4 = 3
(+3) + (-4) =
4–3
-6 + 7 = 7 – 6 = 1
5 + -9 = 9 – 5 = 4
-9 + 9 = 9 – 9 = 0
3
-2
3
=1
1
-4
0
-1
Integer Subtraction Rule
Subtracting a negative number is the
same as adding a positive. Change
the signs and add.
2 – (-7)
is the same as
2 + (+7)
2 + 7 = 9!
Examples
12 – (-8)
-3 – (-11)
12 + (+8)
-3 + (+11)
12 + 8 = 20
-3 + 11 = 8
Integer Multiplication Rule
If the signs are the same, the answer is
positive. If the signs are different the
answer is negative.
3x3=9
-3 x -3 = 9
4 x -5 = -20
-7 x 6 = -42
Integer Division Rule
If the signs are the same, the
answer is positive. If the signs are
different the answer is negative.
(does this look familiar?)
The Hard Part
Integers are easy but the hard part
is Subtracting negatives. Can
you think of a way that helps you
see it in your head?
Please share.