Nine or Ten?
Age 11 to 14
ShortChallenge Level 
Convince yourself that when you roll two dice you are more likely to score 9 than 10.
If I roll 3 dice, which is more likely, a total score of 9, or a total score of 10?
You can find more short problems, arranged by curriculum topic, in our short problems collection.
You may also like
Master Minding
Your partner chooses two beads and places them side by side behind a screen. What is the minimum number of guesses you would need to be sure of guessing the two beads and their positions?
Racing Odds
In a race the odds are: 2 to 1 against the rhinoceros winning and 3 to 2 against the hippopotamus winning. What are the odds against the elephant winning if the race is fair?
Stop or Dare
All you need for this game is a pack of cards. While you play the game, think about strategies that will increase your chances of winning.