Download Adding and Subtracting Integers

Integers
Green counters = positive numbers
=+3
Red counters = negative numbers
= -3
1 green counter and 1 red counter
together – cancel each other out
x x x
x x x
Subtracting
Integers
Subtracting Integers
+4
+2
x x
To subtract,
remove 2 green
2 green (2 positive)
remain
+4 - +2 = +2
Subtracting Integers
-4
-
x x x
To subtract,
remove 3 red
1 red (1 negative)
remains
-3
-4 - -3 = -1
Subtracting Integers
+2
x x x
-
To subtract,
remove 3 green
There aren’t enough green
counters to subtract, so we
will need to add one
To add a green, we also
need to add a red (we add
1 “zero pair”
+3
1 red (1 negative) remains
+2 - +3 = -1
Now we can remove the
final green
Subtracting Integers
-2
x x x
-
To add a red, we also need
to add a green (we add 1
“zero pair”
-3
1 green (1 positive
remains
To subtract,
remove 3 red
There aren’t enough red
counters to subtract, so we
will need to add one
-2 - -3 = +1
Now we can remove the
final red
Subtracting Integers
-2
-
x xx
+3
5 red (5 negative) remain
-2 - +3 = -5
To subtract,
remove 3 green
There aren’t any green
counters to subtract, so we
will need to add 3
To add 3 greens, we also
need to add 3 reds (we add
3 “zero pairs”
Now we can remove 3
greens
Subtracting Integers
+3
xx
-2
5 green (5 positive) remain
+3 - -2 = +5
To subtract,
remove 2 red
There aren’t any red
counters to subtract, so we
will need to add 2
To add 2 red, we also need
to add 2 green (we add 2
“zero pairs”
Now we can remove 2 red
Subtracting Integers
Subtracting is adding the opposite
+
10 – 5 = 5
10 + -5 = 5
Subtracting integers
Subtracting is
adding
-3
+
- 2 = the opposite
+
-3 +
- 2 =
Now, follow the
rules for addition:
Same signs, add
and keep
3+
-
-2
= 5
-
Subtracting integers
Subtracting is
adding
-4
+
- 8 = the opposite
+
-4 +
- 8 =
Now, follow the
rules for addition:
Same signs, add
and keep
4+
-
-8
= 12
-
Subtracting integers
Subtracting is
adding
-6
+
- 9 = the opposite
+
-6 +
- 9 =
Now, follow the
rules for addition:
Same signs, add
and keep
6+
-
-9
= 15
-
Subtracting integers
+
Subtracting is
adding
+
5 - 7 = the opposite
+
- 7 =
+5 +
Now, follow the
rules for addition:
Different signs, subtract, keep the sign of
the higher one
+5
+
-7
= 2
-
Subtracting integers
+
Subtracting is
adding
+
6 - 9 = the opposite
+
- 9 =
+6 +
Now, follow the
rules for addition:
Different signs, subtract, keep the sign of
the higher one
+6
+
-9
= 3
-
Subtracting integers
+
Subtracting is
adding
-
2 - 9 = the opposite
+
- 9 =
+2 +
Now, follow the
rules for addition:
Same signs, add and keep
+2
+
+9
= 11
+
Subtracting integers
+
Subtracting is
adding
-
1 - 6 = the opposite
+
- 6 =
+1 +
Now, follow the
rules for addition:
Same signs, add and keep
+1
+
+6
= 7
+
Subtracting integers
+
Subtracting is
adding
-
5 - 4 = the opposite
+
- 4 =
+5 +
Now, follow the
rules for addition:
Same signs, add and keep
+5
+
+4
= 9
+
Subtracting integers
Subtracting is
adding
-
3 - 6 = the opposite
+
3 +- 6 =
Now, follow the
rules for addition:
Different signs, subtract
Keep the sign of the higher one
-3
+
+6
= 3
+
Subtracting integers
Subtracting is
adding
-
2 - 9 = the opposite
+
2 +- 9 =
Now, follow the
rules for addition:
Different signs, subtract
Keep the sign of the higher one
-2
+
+9
= 7
+
Subtracting integers
Subtracting is
adding
-
7 - 3 = the opposite
+
7 +- 3 =
Now, follow the
rules for addition:
Different signs, subtract
Keep the sign of the higher one
-7
+
+3
= 4
-
Subtracting integers
Subtracting is
adding
-
10 - 1 = the opposite
+
10 +- 1 =
Now, follow the
rules for addition:
Different signs, subtract
Keep the sign of the higher one
-10
+
+1
=9
-
Rule:
KEEP, SWITCH, CHANGE
Keep the sign of the
first number, switch
the subtraction sign to
addition and change
the sign of the second
number