Download To evaluate integer questions that involve multiple signs:

MPM1DI
2- Adding & Subtracting Integers
The addition of integers can be shown by moves on a number line.
- Start at the first integer
- Move to the right for positive integers
- Move to the left for negative integers
To subtract an integer, add its opposite.
Example 1: Evaluate.
a) (+3) + (+4)
b) (-3) + (-4)
c) (+3) + (-4)
d) (-3) + (+4)
When evaluating expressions, keep in mind that:
If the numbers have the same sign, then add up the numbers and carry the sign.
If the numbers have different signs, then
 add the integers with the same sign
 Find the difference between the two numbers and carry the sign of the number that
is the greater distance from zero
Evaluate -7 + 2 - 5 + 6 using a Scoreboard approach.
+
-
Example 2: Evaluate the following.
a) (+1) - (-6) - (+3) - (-4)
Place the numbers under the appropriate heading
Determine each team’s final score
Which team won?
By how much?
b) (-2) - (+6) - (-4) - (+7)
c) 7 - 2 - 6 + 4 - 8 + 2
Example 3: The time difference between Toronto and Vancouver is 3 hours.
a) An airplane leaves Vancouver for Toronto at 89:00 and the flying time is 4 hours and 10 minutes. What
time does it arrive in Toronto?
b) On the return flight the airplane leaves Toronto at 7:30 and the flying time to Vancouver is 4 h and 30 min.
What tie does it arrive in Vancouver?
Homework: Pg. 8: #1acegik, 3aceg, 4ace
Pg. 13: #5acdfgijlmo
Pg. 14: #8aceg, 9acegi, 10acegi