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Problems Archives

The problems archives table shows problems 1 to 746. If you would like to tackle the 10 most recently published problems then go to Recent problems.
Click the description/title of the problem to view details and submit your answer.


ID

Description / TitleSolved By
151Paper sheets of standard sizes: an expected-value problem
5292
152Writing 1/2 as a sum of inverse squares
2540
153Investigating Gaussian Integers
2481
154Exploring Pascal's pyramid
2506
155Counting Capacitor Circuits
3411
156Counting Digits
2285
157Solving the diophantine equation 1/a+1/b= p/10n
2562
158Exploring strings for which only one character comes lexicographically after its neighbour to the left
3447
159Digital root sums of factorisations
3146
160Factorial trailing digits
3330
161Triominoes
1990
162Hexadecimal numbers
5149
163Cross-hatched triangles
1710
164Numbers for which no three consecutive digits have a sum greater than a given value
5522
165Intersections
2449
166Criss Cross
3893
167Investigating Ulam sequences
1584
168Number Rotations
2522
169Exploring the number of different ways a number can be expressed as a sum of powers of 2
4827
170Find the largest 0 to 9 pandigital that can be formed by concatenating products
1872
171Finding numbers for which the sum of the squares of the digits is a square
2617
172Investigating numbers with few repeated digits
3619
173Using up to one million tiles how many different "hollow" square laminae can be formed?
8803
174Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements
5626
175Fractions involving the number of different ways a number can be expressed as a sum of powers of 2
1668
176Right-angled triangles that share a cathetus
1795
177Integer angled Quadrilaterals
1196
178Step Numbers
3237
179Consecutive positive divisors
10908
180Rational zeros of a function of three variables
1490
181Investigating in how many ways objects of two different colours can be grouped
1873
182RSA encryption
2484
183Maximum product of parts
4499
184Triangles containing the origin
1539
185Number Mind
2965
186Connectedness of a network
2707
187Semiprimes
10839
188The hyperexponentiation of a number
6163
189Tri-colouring a triangular grid
1933
190Maximising a weighted product
3977
191Prize Strings
6812
192Best Approximations
1502
193Squarefree Numbers
3135
194Coloured Configurations
1303
195Inscribed circles of triangles with one angle of 60 degrees
1300
196Prime triplets
2428
197Investigating the behaviour of a recursively defined sequence
4716
198Ambiguous Numbers
1045
199Iterative Circle Packing
1833
200Find the 200th prime-proof sqube containing the contiguous sub-string "200"
2227