U1D2 Notes - Subtraction of Integers
Name: ____________________________________
What is a negative sign versus a positive sign? What directions do they move? Explain.
VOCABULARY
Difference – the ___________________ of two (or more) numbers.
Subtracting a Positive or Adding a Negative Integer is just simple subtraction. How do the directions work?
Example: 8 – (+2) = ___________ = _____ is really saying "Positive 8 minus Positive 2 equals Positive 6"
Example: 4 + (–7) = ___________ = _____ is really saying "Positive 4 plus Negative 7 equals Negative 3"
Subtracting a Positive or Adding a Negative Integer moves to the _____________ direction, as shown:
Subtracting Positive Integers is just simple subtraction. What is the direction of travel? _____________
Example: 6 − 3 = 3 is really saying "Positive 6 minus Positive 3 equals Positive 3"
Let’s Try a Few:
A) 7 + (−1) =
B) 5 − 2 =
C) 3 + −15 =
D) 12 − 13 =
E) −6 − (1) =
F) 5 + (−3) =
G) |2 − 11| =
H) −27 − (10) =
I) −2 + 5 =
J) −7 − |10| =
K) 24 + |−4| =
L) |−18 − 5| =
Example: What is going on here?
A) 5 − 5 =
B) −5 + 5 =
C) |5 − 5| =
D) |−5 + 5| =
Subtracting Negative Integers is the same as addition. What is the direction of travel? _____________ Why?
Example: 6 – (–3) = ____________= _____ is really saying "Positive 6 minus Negative 3 equals Positive 9"
Example: –7 – (–8) = ____________= _____ is really saying "Negative 7 minus Negative 8 equals Positive 1"
Let’s Try Some More:
A) 7 − (−1) =
B) −2 − −5 =
C) 3 − −15 =
D) −12 − (−13) =
E) −5 − 3 =
F) 8 − (−11) =
G) −27 − (−10) =
H) |9 − −3| =
I) 24 − |−4| =
J) |−6 − −7| =
K) The difference of 10 and 2 =
L) Find the difference of 8 and -5. Show this result on the number line:
Subtracting Numbers in Everyday Life
Example: You have nothing in your bank account, but you owe the bank a $25 fee for an overdraft charge.
You call the bank operator to complain, and they decide to waive the fee to make the customer happy. This is
an instance of removing a negative fee, which can be thought of as: “subtracting a negative which is equivalent to _________________________.”
0 − (−25) = ____________________
Example: An elevator went up 13 floors then down 7 floors. What is the current floor?
Example: I earned $55 and then spent $32. How much is left?
Example: Jericho, the oldest inhabited town in the world, lies 853 feet below sea level (-853), making it the
lowest town on earth. Mount Everest is the highest mountain in the world, standing at 8850 meters (+8850),
nearly 5.5 miles above sea level. What is the difference in elevation between Jericho and Mount Everest?
Show all of your work.
Then complete Pages 4-10 of your Student Workbook – Number Sense. Keep your workbook in your binder,
as we will be adding pages to the workbook throughout the semester.