Joyful Math, why not?

Finding the surface area of sphere
Materials:
Orange
Plain paper

Steps:
1. Tell the students that we are going to discover the formula for the surface area of a sphere
2. Organize students into groups of four or five
3. Give each group an orange
4. Ask the students to cut the orange into two parts horizontally
5. Ask the students to put the hemi-orange on the paper so that they can draw circle according to the circumference of the flat part of the hemi-orange
6. Ask the students to draw the circles as many as they want
7. Then ask the students to tear the husk of the orange into small pieces
8. The next step is arrange those pieces till they can cover the circles completely
9. Ask the students to count how many circles that can be covered by the pieces
10. The students will then discover that there are four circles covered
11. From this activity, the students will know that the surface area of a sphere is four times the area of circle

Finding mean, median, and mode of single data
Materials
Candies

Steps:
1. Tell the students that we are going to learn about central tendency of single data
2. Give each students a pack containing candies of different amount
3. Ask the students not to open the pack yet
4. Ask the students to open the pack together
5. Ask the students to count the number of candies the get
6. Ask the students to come forward and stand in line according to the number of candies they get, from the least to the greatest
7. Ask the students to number themselves (1, 2, 3, ……)
8. Ask the students to determine the one who is in the middle position
9. Tell the students that the number of candies the middle student gets is called media
10. Ask the students to formulate a definition about median
11. Then, ask the student to gather with their friends who get the same number of candies
12. Ask the students to determine which the most popular group (the group with the greatest member)
13. Tell the students that the number of candies the most popular group get is called mode
14. Ask the students to formulate a definition about mode
15. After that, ask the students to share the candies fairly so that each student will get the same number of candies
16. Tell the students that the number of candies they get after sharing fairly is called mean
17. Ask the students to formulate a definition about mean
18. Tell the students to get back to their seats
19. Then, explain to the students the correct definition of mean, median, and mode
20. Ask the students to examine their own definitions and compare with the correct ones.