Age

5 to 14

**To celebrate NRICH's 25th birthday, we have created a special version of one of our favourite games, Got It.**

Got It is a game for two players.

The **challenge** is to be the **first player to hit the target of 25** (as a celebration of NRICH's birthday!).

- You can play against the computer or with a friend.
- The first player chooses a whole number from 1 to 5.
- The second player chooses a whole number from 1 to 5, which is added onto the first player's number to make a new total.
- Play continues in this way, with players taking turns to add a whole number from 1 to 5 to the running total.
- The winner is the player who reaches the target of 25.

#### Play the game several times.

- Can you find a winning strategy?
- Can you always win?

Does your strategy depend on whether or not you go first?

To change the game, choose a new Got It target or a new range of numbers to add on.

Test out the strategy you found earlier. Does it need adapting?

- Can you work out a winning strategy for any target?
- Can you work out a winning strategy for any range of numbers?
- Is it best to start the game? Always?

Away from the computer, challenge your friends:

One of you names the target and range and lets the other player start.**Extensions:**

- Can you play without writing anything down?
- Consider playing the game where a player CANNOT add the same number as that used previously by the opponent.