2. Math Club Presentation. By : Se Jin An Se Jin An4B

3. The Problem :

4. Making Sense of the Problem. What is the Question? What is the Question? Need 2 Know VS Know Need 2 Know VS Know

5. What is the question? What is the telephone number that adds up to 47?

6. NEED to Know VS Know N2K | Know | - Addition | - 8 digits - If the tens | - Sum digits are | - Has to | equal allowed | 47 |

7. How to solve the problem ( Clue #1) Use the multiplication chart : Use the multiplication chart : The KEY Green = less than 47 Red = more than 47

8. 9X9 (Clue #2) 9X9 = 45 9X9 = 45 45 is the most closest to 47 in the table. 45 is the most closest to 47 in the table. So there would be 9,9,9,9,9 So there would be 9,9,9,9,9

9. 8 Digits (Clue #3) To be a 8 digit number, we need 3 more digits. To be a 8 digit number, we need 3 more digits.

10. 2 More (Clue #4) We have 45 and we need 2 more. We have 45 and we need 2 more.

11. We can’t! (Clue #5) We can’t divide 2÷3 so we take one from the 9 so one 9 has to be a 8. We can’t divide 2÷3 so we take one from the 9 so one 9 has to be a 8.

12. Now we can! (Clue #6) Now we can divide 2÷3! Now we can divide 2÷3! 2+1(from the nine)=3 2+1(from the nine)=3 3÷3= 1 3÷3= 1

13. The Solution The solution I had is 91918919 The solution I had is 91918919 But there is more than 1 solution to this problem. But there is more than 1 solution to this problem.

14. Why? My solution was correct because it had what it asked for.(8 digits and a sum of 47). My solution was correct because it had what it asked for.(8 digits and a sum of 47).