October 01, 2010
Section 2-2 and 2-3
Adding and Subtracting Integers
October 01, 2010
Get out a piece of paper.
Put "2-2 & 2-3: Adding and subtracting Integers" at the top
Draw a number line under that (like the one below)
-10
-9
-8
-7
-6
-5 -4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
10
October 01, 2010
Adding Integers
-10
-9
-8
-7
-5 + (-3) =
-9 + -1 =
-6
-5 -4
-3
-2
-1
0
1
2
3
4
5
6
7
8
-2 + -8 =
-9 + -5 =
0 + -8 =
-2 + -6 =
-5 + 2 =
-6 + 8 =
5 + (-4) =
7 + -3 =
-4 + 12 =
10 + -5 =
9
10
October 01, 2010
Have you thought of the rule? What can I do when I am adding two
integers so I don't have to keep using a number line each time?
Try these WITHOUT using the number line-- you can check
yourself with a number line if you need to after you have finished.
-20 + 2 =
-12 + (-5) =
-18 + -62 =
28 + (-3) =
October 01, 2010
(Tune of Row, Row, Row your boat)
Same signs add and keep
Opposites subtract
Give it the sign of the larger one
And then you'll be exact!!!
October 01, 2010
Practice time...
-7 + 8 =
-16 + 7 =
-10 + -35 =
14 + -10 =
October 01, 2010
Evaluate c + d for the given values
c = 6, d = -20
c = -45, d = 32
c = -8, d = -21
October 01, 2010
Subtracting Integers
-10
-9
-8
7 - 12 =
2 - (-6) =
-10 - (-7) =
-3 - (-3) =
-5 - (-9) =
1 - (-3) =
-4 - 2 =
-7
-6
-5 -4
-3
-2
-1
0
1
2
3
4
5
6
7
8
9
10
October 01, 2010
Have you thought of the rule? What can I do each time when
subtracting two integers so I don't have to keep using the number
line?
Try these WITHOUT using the number line.
-12 - (-2)=
4-7=
-6 - 5 =
-8 - (-2) =
October 01, 2010
(If your happy and you know it)
If you're subtracting and you know it-LCC!
(clap, clap)
If you're subtracting and you know it-LCC!
(clap, clap)
If your subtracting and you know itThen your work will surely show it.
If you're subtracting and you know it-LCC!
(clap, clap)
October 01, 2010
Practice Time!!
-18 - (-18) =
22 - (-8) =
9 - 15 =
- 7 - (-12) =
10 - (-9) =
October 01, 2010
6 + (-5) - 3 =
Evaluate a - b for a = 9 and b = -7
5 - (-8) - (-3) =
October 01, 2010