## Year 2 Lesson Plan 24 (LAST LESSON) - Volumes, Absolute Values

This lesson is meant to be the last lesson. If you curriculum has room for 25 lessons, then this should be the last one. Teach lesson 25 first, and then use this as the last lesson. It is a review of vocabulary and a brief exercise in volumes and absolute values (both easy concepts.)
1. (5 min) Mental Math
1. What is the square root of 36? [6]
2. What is square root of 49? [7]
3. What is square root of 81? [9]
4. What is cube root of 8? [2]
5. What is cube root of 27? [3]

2. (10 min) VOLUMES
To calculate the volume of a 3-dimensional geometrical solid, find the area of the base and multiply by its height. Volumes are expressed in cubic units. Here are some formulas for volumes:
• Rectangular prism (a box): volume = length x width x height
Example: A box that is 3 by 4 by 5 feet has a volume of 60 cu ft.
• Cube whose side has length S: S x S x S
Example: A cube whose side is 3 inches long: volume = 27 cu in.
• Cylinder: volume = base x height = pi x r2 x h
Example: Radius = 2, height = 5, volume = 20 pi or 62.8
• Triangular prism: volume = base x height = (length x width/2) x height
Example: Length = 2, width = 3, height = 4, volume = 12

3. ABSOLUTE VALUES
Absolute value is the positive value of a number. It is written with straight bars on each side: | - 6 | = 6 and also | 6 | = 6.
For x = - 5, | x | = 5
Why is this important? Well it gives us the size of a number without worrying about its sign. It is useful in calculating distance from point A to point B when point B is smaller than point A.

4. In-class exercise. No homework this week. This is the last week!

5. MATH JEOPARDY
This week's competition is Math Jeopardy. You play it with the class using the rules of jeopardy. This game is a change of pace and gives the kids some interesting practice on vocabulary. If they do not know a word, explain it to them as you go. You can explain the answers, too as you go along.

The kids take turns picking a category and value, you read the questions, and the first kid with a hand up gets to answer. Answers must be phrased in the form of a question. If you read: "the first even number" the correct answer is "What is 4?" Paper and pencil are OK. Calculators are OK, although they will be a big disadvantage, as they will slow the kid down.

Give 1 of a prize (1 M&M or 1 Skittle) for a \$100 answer, 2 for a \$200 answer, and 10 for a \$1000 answer. The kids may either eat their earnings or save them to bet on Final Jeopardy. Two big bags of candies should be enough--you will need about 400 pieces to play the entire thing.

Here are some hints about how to adapt this to make it more successful:
• Use a transparency projector to display the grid of choices and mark them off as the kids get the answers.
• Instead of displaying the choices, display the questions which have been covered up by little Post-it notes (1/5" by 2" size) Remove the Post-it notes to reveal the questions.
• If one kid dominates the answers, (highly probable) take turns going around the room letting each kid have a turn at a question. If a kid cannot answer the question she or he chose, then pick on someone else who has a hand up. This ensures that everyone is thinking about the question, as they may get a chance as a backup.
• If you have too many kids to play, try forming them into teams of 4 with a spokesman captain. Give the team 15 seconds to answer the question before calling on someone else. In this case, everyone on the team would get the prize.