Exploring and noticing

  • 12345
    problem

    12345

    Age
    14 to 16
    Challenge level
    filled star filled star empty star
    Repeat a pattern of numbers to form a larger number. Can you find the sum of all the digits?
  • Path to the Stars
    problem

    Path to the Stars

    Age
    7 to 11
    Challenge level
    filled star filled star empty star
    Is it possible to draw a 5-pointed star without taking your pencil off the paper? Is it possible to draw a 6-pointed star in the same way without taking your pen off?
  • Arrange the Digits
    problem

    Arrange the Digits

    Age
    11 to 14
    Challenge level
    filled star filled star empty star
    Can you arrange the digits 1,2,3,4,5,6,7,8,9 into three 3-digit numbers such that their total is close to 1500?
  • Out of Sync
    problem

    Out of Sync

    Age
    11 to 14
    Challenge level
    filled star filled star empty star
    Albert Einstein could see two clocks which were out of sync. For what fraction of the day did they show the same time?
  • Newspaper Sheets
    problem

    Newspaper Sheets

    Age
    14 to 16
    Challenge level
    filled star filled star empty star
    From only the page numbers on one sheet of newspaper, can you work out how many sheets there are altogether?
  • Take a Leaf
    problem

    Take a Leaf

    Age
    11 to 14
    Challenge level
    filled star filled star empty star
    An examination paper is made from five pieces of paper. What is the sum of the other page numbers that appear on the same sheet as page 5?
  • Collatz-ish
    problem

    Collatz-Ish

    Age
    14 to 16
    Challenge level
    filled star filled star empty star
    A sequence is generated using these rules. For which values of n is the nth term equal to n?
  • Halloween Day
    problem

    Halloween Day

    Age
    11 to 14
    Challenge level
    filled star filled star empty star
    One year there were exactly four Tuesdays and four Fridays in October. On what day of the week was Halloween.
  • Back in Time
    problem

    Back in Time

    Age
    14 to 16
    Challenge level
    filled star filled star empty star
    How many times a day does a 24 hour digital clock look the same when reflected in a horizontal line?
  • How many Rectangles?
    problem

    How Many Rectangles?

    Age
    11 to 14
    Challenge level
    filled star filled star empty star
    By drawing 5 horizontal and four vertical lines, one can form 12 rectangles. What is the greatest number of rectangles that can be formed by drawing 15 lines?