October 30, 2014
Lesson 2.4: Subtracting Integers with Tiles
Focus: Use colored tiles to subtract integers.
You can also use tiles to subtract integers!
Let's use counters to model how to subtract whole numbers.
For example: use tiles to subtract:
1) (+7) - (+2)
2) (+3) - (-2)
Explore (p. 66):
Use tiles to subtract:
1. (+5) - (+3)
3. (-3) - (+5)
2. (+5) - (-3)
4. (-3) - (-5)
October 30, 2014
1) Explain in words how did you subtracted (+5) - (+3)?
2) a) Explain in words what you did to subtract (+5) - (-3)?
b) What happened when you tried to subtract (-3)?
3) a) In words how did you subtract (-3) - (-5)?
b) What did you do to take +5 away from -3?
4) For which subtraction pair did you NOT have to use zero pairs?
Connect:
Share your results and the strategies you used to subtract integers.
Think about the integers you used in "Explore".
For what other subtraction problems would we not need to use zero pairs?
How do we know when we don't need to add zero pairs?
When the integers have the ____________, and the integer I
take away is __________________________ than the
integer _______________________________.
How do you know when you need to add zero pairs?
1) When the integers have __________________
2) When both are _________ and the integer I am taking away is _________ than
the integer I am taking it ________
3) When both are _________ and the integer I am taking away is _________ than
the integer I am taking it ________
October 30, 2014
Model and solve:
Use colored tiles to model:
1) (+5) - (+9)
2) (+2) - (-6)
3) (-2) - (-6)
4) (-6) - (+2)
Homework:
p. 69 # 1, 3, 5, 8, 9