Lesson Plan #21 - Squares, Cubes and
Square Roots
- (5 min) Mental Math
- What is the probability of flipping a coin twice
and getting a
'heads' both times? [1/4]
- Start with 2700, divide by 100, then divide by 3 [9]
- What is the probability of drawing a black 8
out of a deck of 52 cards? [1/26]
- What is 30% of 90? [27]
- Multiply 1/3 by 3/4 and reduce [1/4]
- (5 min) Review of homework #18 (<= 3 problems)
- (10 min) Introduce squares,cubes and square roots:
- Pass out the "Squares, Cubes, and Square Roots" handout.
- Follow the discussion in the handout.
- Have students fill out the table on the first page of the
handout.
- Follow the "Square Root" discussion on the second page of the
handout.
- Have the students fill out the table on the second page of the
handout.
- Show students the square root key on the calculator. Do a few simple
square roots using this key.
- Discuss the solution of equations with squares:
Example 1: | x2 + 4 = 20 | Solution: x =
4 |
Example 2: | 40 - x2 = 4 | Solution: x =
6 |
Example 3: | 2x2 - 1 = 17 | Solution: x =
3 |
Have them use the "Cover up" technique they already know to solve
these equations.
- (Remainder of class) In-class Exercise.
- Hand out homework as students successfully complete the in-class
exercise.
Note:
Students have a tendency to compute squares as multiplies by
2:52 = 5 x 2 = 10
This is reinforced by the fact that it works for 2:
22 = 2 x 2 = 4
Watch for this!! |
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