Year 2 Lesson Plan 17 - Probability

1. (5 min) Mental Math
1. Divide 6000 by 100, add 16, then divide by 2 [38]
2. Divide 3/4 by 2/3 and subtract 1 [1/8]
3. What is 1/7 - 1/8? [1/56]
4. If x - 5 is 13, what is x? [18]
5. If x is 50, what is 4x - x + 1? [151]

2. (10 min)Discuss probability

Follow the discussion on the handout. Use your own discretion as to whether you actually hand this explanation out. You may want to just use it for your own notes, or hand it out as class ends.

As you go through this lesson, point out that you can get very large numbers (too large for your calculator) unless you cancel first. There are 3 useful fraction simplifications to remember:

13/52 = 1/4
4/52 = 1/13
3/51 = 1/17

This lesson can be made more graphic by bringing in a deck of cards and a pair of dice to illustrate your concepts. They can be laid out on the floor so the students can see the possibilities.
3. (Remainder of class) In-class exercise

4. Hand out homework as students successfully complete the in-class exercise.