Essential Question: Why are and both real numbers?
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Essential Question: Why are and both real numbers?
Shoot For The Stars
30 seconds
 I got this! I know this word AND I could even teach it to somebody else.
 I think I know this word, but I need more practice.
 I am clueless! I have no idea what this word means.

Essential Question: Why are and both real numbers?
Perfect Cube:
Cube Root:
The opposite of cubing a number. That means finding the length of a cube’s side from it’s volume.
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Essential Question: Why are and both real numbers?
3
2
1
cube.
1
3 =
1 2
3 =
8 3
3 =
27
The cube of an integer is a perfect
The opposite of cubing a number is taking the cube root.

Essential Question: Why are and both real numbers?
 For example 3
125
Means… if a cube has a volume of 125, then how big is one of it ’s sides?
In other words, what number multiplied by itself three times in a row is equal to 125?
That number is 5.
5

Essential Question: Why are and both real numbers?
Simplify each square root on your iPad
3
8
3 27 3
______

Essential Question: Why are and both real numbers?
But watch this…
3 -
8
Possible: Because any negative number multiplied by itself three times in a row still equals a negative answer.
3
8
-2
______
Possible: Since the negative sign is on the OUTSIDE of the cube root sign, it just means “what number is the opposite of the cube root of 8?”

Essential Question: Why are and both real numbers?
 Do you see that cubes and cube roots are inverses (opposites) of each other?

Essential Question: Why are and both real numbers?

Essential Question: Why are and both real numbers?
 Quote of the Day:
“ You always pass failure on the way to success.
”

Essential Question: Why are and both real numbers?
 Once we have memorized the perfect cubes from 1 to 10 and their roots, we can estimate irrational cube roots that are not perfect cubes.
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Essential Question: Why are and both real numbers?
 We already know the two perfect cubes that are before and after the cube root of 11. . .

3 8 and
3 27
 Look at them on the number line on the board:

Essential Question: Why are and both real numbers?
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11 more than 2, or approximately 2.1.
11

Essential Question: Why are and both real numbers?
TRY THIS:
What two perfect cube roots come before and after the non-perfect cube roots below? Use your iPad.
3
147
3
125
3
216
3
15
3
8
3
27
3
411
3
343
3
512

Essential Question: Why are and both real numbers?
TRY THIS:
What two whole numbers on the number line come before and after the non-perfect cube roots below? Use your iPad.
3
79 4 And 5
3
303
3
275
6 And 7
6 And 7

Essential Question: Why are and both real numbers?
 Step 1 – Spend 20 seconds thinking silently about the
Essential Question.
 Step 2 – Spend 30 seconds pairing up with your learning partner.
 Step 3 – Volunteer to share your answer with the class…
Volunteers will receive a Goodybuck.