Celebrate 25 Years of NRICH

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.