SUBTRACTING INTEGERS 11 3 NOTES SUBTRACTING INTEGERS Use
SUBTRACTING INTEGERS
11. 3 NOTES SUBTRACTING INTEGERS • Use Keep, Switch, Flip to convert a Subtraction question into an Addition. +5 +- (+6) (-6)= +11 Keep Switch Flip
I can… Subtract positive integers Ø Subtract negative and positive integers Ø Self Assessment 54321 - I I I can do it without help & teach others. can do this with no help, but I don’t know if I can explain it. can do this with a little help. can do this with a lot of help! don’t have a clue.
Using the Number Line Step 1: Starting at 0, plot the first integer on the number line. Step 2: Plot the second integer on the number line beginning where the last number left off (be sure to look at the sign. 3 - 5 = -2 -5 3
Using the Number Line Step 1: Starting at 0, plot the first integer on the number line. Step 2: When you subtract a negative number you move to the right 2 – (-4) = -6 2 -4
SO YOU THINK YOU CAN ADD INTEGERS? • We have mastered the fine art of adding positive and negative integers using number lines and counters +3 + (-4) = -1 - 6 + (- 7) = -13
WE ALREADY KNOW HOW TO ADD…. • So why would we need to know how to subtract? • When we are not using counters or number lines we don’t need to! • Remember all the way back to yesterday • Every integer has an opposite number +9 and -9 +20 -4 and +4 -20 and
WHAT DOES THAT HAVE TO DO WITH ANYTHING? • Well through a simple process we can convert a Subtraction question into an Addition. • It’s called keep * switch * flip
WHAT DO WE DO? • Its very simple +5 +- (+6) (-6)= +11 Keep Switch Flip
ONE MORE TIME! +9 Keep +- (-7) (+7)= +2 Switch Flip
PRACTICE 2 – 10 = a. 8 b. -8 c. 12 d. -12
PRACTICE 2 – 10 = a. 8 b. -8 c. 12 d. -12
-5 - 15 a. 10 b. -10 c. 20 d. -20
-5 - 15 a. 10 b. -10 c. 20 d. -20
10 – (-4) a. 6 b. -6 c. 14 d. -14
10 – (-4) a. 6 b. -6 c. 14 d. -14
SO…. • Never subtract Integers!
I can… Subtract positive integers Ø Subtract negative and positive integers Ø Self Assessment 54321 - I I I can do it without help & teach others. can do this with no help, but I don’t know if I can explain it. can do this with a little help. can do this with a lot of help! don’t have a clue.
11. 3 NOTES SUBTRACTING INTEGERS • Use Keep, Switch, Flip to convert a Subtraction question into an Addition. +5 +- (+6) (-6)= +11 Keep Switch Flip
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