Subtraction of Integers

2. Learning Target:
c. solve routine and non-routine problems
involving subtraction of integers using
appropriate strategies and tools.
a. perform subtraction of integers
through algebra tiles, counters, chips,
cards and number line;
b. cooperate with one’s group
mates in making an output; and

3. The grade 6 classes in a school collected 4
sacks of rice for their outreach activity.
One sack of rice was given to a needy
family. How many sacks of rice were left?
What operation should be used to solve the problem above?
MATHEMATICAL SENTENCE: +4 - +1 = N
Solution:
+4 - +1 = +3
4 units
1 units
Answer: There were 3 sacks of rice left.
+4 + -1 = +3

5. MATHEMATICAL SENTENCE: +4 - -1 = N
Solution: +4 - -1 = N
+5
+4 +1
+

6. MATHEMATICAL SENTENCE: +4 - -1 = N
Let us use tiles to illustrate +4 - -1 = N
+1 +1
+1 +1
-1
+1 +1
+1 +1
+1
- = + =+1 +1
+1 +1
+1

7. In Seoul, South Korea, the temperature is -
17OC in the morning. By afternoon, the
temperature becomes -12OC. What is the
difference between the temperature in the
morning and in the afternoon?
What operation should be used to solve the problem above?
MATHEMATICAL SENTENCE: -17 - -12 = N
Solution:
Answer: The difference of the temperature in the morning and in the afternoon is -5OC
+
-17 +12
-5

8. +9 - +2 =
+8 - +3 =
-8 - -5 =
-6 - -2 =
+7
+5
-3
-4

9. KEEP the
sign of the
first
number
CHANGE
the sign of
the
second
number
CHANGE
subtraction
to addition

13. Solve each

14. Solve each

15. Solve each

16. Solve each

17. Solve each

18. Solve each

19. Solve each

20. Solve each

21. Solve each

22. Solve each

23. Identify if the statement is:
A Always
True
Sometimes
True
s
Never
True
N

24. A Always
True
Sometimes
True
s
Never
True
N
The sum
of two
positive
integers is
positive.

25. A Always
True
Sometimes
True
s
Never
True
N
The sum of a
positive
integer and a
negative
integer is
positive.

26. A Always
True
Sometimes
True
s
Never
True
N
The
difference
of two
positive
integers is
positive.

27. A Always
True
Sometimes
True
s
Never
True
N
The sum
of two
negative
integers is
negative.

28. A Always
True
Sometimes
True
s
Never
True
N
The
absolute
value of -
23 is -23.

29. A Always
True
Sometimes
True
s
Never
True
N
The
opposite
of 17 is -
17.

30. A Always
True
Sometimes
True
s
Never
True
N
The sum
of 18 and
(-7) is 25.

31. A Always
True
Sometimes
True
s
Never
True
N
The
difference
of two
negative
integers is
negative.