I am thinking of a number between 1 and 100. What's my number?
Look at the eight clues below.
Can you sort out the four clues that enable you to deduce my number?
Which four clues are not necessary, even though they are true?
- The number is greater than $9$.
- The number is not a multiple of $10$.
- The number is a multiple of $7$.
- The number is odd.
- The number is not a multiple of $11$.
- The number is less than $200$.
- Its ones digit is larger than its tens digit.
- Its tens digit is odd.
Choose your own secret number between 1 and 100.
Write exactly four clues so that your friend needs each of them to guess your number.
Try it out on your friend.
Remember, avoid clues that double-up and therefore are not needed such as both 'it's even' and 'it's in the 4 times table'. Your four clues must lead to just one number between 1 and 100.