This is part of our collection of Short Problems.
You may also be interested in our longer problems on Patterns and Sequences Age 11-14 and Age 14-16.
Printable worksheets containing selections of these problems are available here.
problem
Fibonacci deduction
Leonard writes down a sequence of numbers. Can you find a formula to predict the seventh number in his sequence?
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Fruit line-up
This grocer wants to arrange his fruit in a particular order, can you help him?
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Printing error
Every third page number in this book has been omitted. Can you work out what number will be on the last page?
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What a coincidence!
Consider two arithmetic sequences: 1998, 2005, 2012,... and 1996, 2005, 2014,... Which numbers will appear in both?
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Street lamps
Walking up a steep hill, I pass 10 equally spaced street lamps. How long do I take to walk from the first lamp to the last?
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Triangular clock
Trinni rearanges numbers on a clock face so each adjacent pair add up to a triangle number... What number did she put where 6 would usually be?
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Pattern snake
This pattern repeats every 12 dots. Can you work out what a later piece will be?
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Hexagon line
How many hexagons are required for the perimeter of the whole shape to have length 1002cm?
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How many rectangles?
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?
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Knockdown
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?
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?
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Night watchmen
Grannie's watch gains 30 minutes every hour, whilst Grandpa's watch loses 30 minutes every hour. What is the correct time when their watches next agree?
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Knights and knaves
Knights always tell the truth. Knaves always lie. Can you catch these knights and knaves out?
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Doubly consecutive sums
How many numbers less than 2017 are both the sum of two consecutive integers and the sum of five consecutive integers?
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Even up
Consider all of the five digit numbers which we can form using only the digits 2, 4, 6 and 8. If these numbers are arranged in ascending order, what is the 512th number?
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12345
Repeat a pattern of numbers to form a larger number. Can you find the sum of all the digits?
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Newspaper sheets
From only the page numbers on one sheet of newspaper, can you work out how many sheets there are altogether?
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Collatz 13
If a number is even, halve it; if odd, treble it and add 1. If a sequence starts at 13, what will be the value of the 2008th term?
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Collatz-ish
A sequence is generated using these rules. For which values of n is the nth term equal to n?
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Trolley park
In a supermarket, there are two lines of tightly packed trolleys. What is the length of one trolley?