Interesting Mathematics

The tasks of the Latvian team.

1. Why are numbers placed in this order?8, 5, 4, 9, 1, 7, 6, 3, 2.

If you write the numbers as words:Eight ,Five,Four,Nine,One,Seven,Six,Three,Two,you can see they are in alphabetical order.

2. There is some sequence given7, 15, 31, 63, …What is the basis of this sequence?

7+(7+1)=15;15+(15+1)=31;31+(31+1)=63.

3. Now Erudit is three times younger than his father. But 5 years ago he was four times younger than his father. How old are Erudit and his father?

Erudit is 15 years old.

His father is 45 years old.

4. In the house there are Erudit and his five brothers. All of them are busy. One is playing the piano, another one is reading, the third brother is playing chess, the fourth is watching TV, the fifth is solving a crossword puzzle. What is doing Erudit?

Erudit is playing chess.

5. Change the place of three matches so that you have three equal squares.

6. Change the place of three matches so that the arrow changes its direction.

7. Matches make an incorrect equation. Change the place of one match so that the equation is correct.

8. A puzzle “A glass with cherry”.Change the place of two matches so that the cherry is not in the glass. It is allowed to change the position of the glass, but it shape can’t be changed.

9. When my father was 31 years old, I was 8 years old. Now my father is two times older than me. How old am I now?

You are 23 years old.

10. One person was asked: ”How old are you?”“A lot” – was the answer.“I am older than some of my relatives six hundred times.” Is it possible?

I think that it is possible and maybe he is 50 years old, and his grandson just a month! Then grandfather will be older his grandson 600 times, he lived for 600 months, and a baby only month.