Challenge Level

A pattern repeats every six symbols. What are the 100th and 101st symbols?

Challenge Level

How many arm-wrestles will there be in the royal arm wrestling championship?

Challenge Level

Weekly Problem 51 - 2016

Pegs numbered 1 to 50 are placed in a row. Alternate pegs are knocked down, and this process is repeated. What is the number of the last peg to be knocked down?

Challenge Level

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?

Challenge Level

Albert Einstein could see two clocks which were out of sync. For what fraction of the day did they show the same time?

Challenge Level

One year there were exactly four Tuesdays and four Fridays in October. On what day of the week was Halloween.

Challenge Level

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?

Challenge Level

Weekly Problem 24 - 2012

Can you put these very close fractions into order?

Challenge Level

How many 10-digit numbers containing only 1s, 2s and 3s can you write?

Challenge Level

From only the page numbers on one sheet of newspaper, can you work out how many sheets there are altogether?

Challenge Level

A sequence is generated using these rules. For which values of n is the nth term equal to n?

Challenge Level

Repeat a pattern of numbers to form a larger number. Can you find the sum of all the digits?

Challenge Level

How many times a day does a 24 hour digital clock look the same when reflected in a horizontal line?