Cache update: 49 minutes

Problems Archives

The problems archives table shows problems 1 to 661. 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.


IDDescription / TitleSolved By
151Paper sheets of standard sizes: an expected-value problem
4675
152Writing 1/2 as a sum of inverse squares
2179
153Investigating Gaussian Integers
2143
154Exploring Pascal's pyramid
2175
155Counting Capacitor Circuits
2991
156Counting Digits
1971
157Solving the diophantine equation 1/a+1/b= p/10n
2218
158Exploring strings for which only one character comes lexicographically after its neighbour to the left
3050
159Digital root sums of factorisations
2749
160Factorial trailing digits
2913
161Triominoes
1714
162Hexadecimal numbers
4614
163Cross-hatched triangles
1494
164Numbers for which no three consecutive digits have a sum greater than a given value
4911
165Intersections
2156
166Criss Cross
3433
167Investigating Ulam sequences
1391
168Number Rotations
2218
169Exploring the number of different ways a number can be expressed as a sum of powers of 2
4329
170Find the largest 0 to 9 pandigital that can be formed by concatenating products
1615
171Finding numbers for which the sum of the squares of the digits is a square
2297
172Investigating numbers with few repeated digits
3203
173Using up to one million tiles how many different "hollow" square laminae can be formed?
7991
174Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements
5094
175Fractions involving the number of different ways a number can be expressed as a sum of powers of 2
1477
176Right-angled triangles that share a cathetus
1590
177Integer angled Quadrilaterals
1039
178Step Numbers
2834
179Consecutive positive divisors
9838
180Rational zeros of a function of three variables
1298
181Investigating in how many ways objects of two different colours can be grouped
1655
182RSA encryption
2205
183Maximum product of parts
4045
184Triangles containing the origin
1327
185Number Mind
2634
186Connectedness of a network
2401
187Semiprimes
9817
188The hyperexponentiation of a number
5604
189Tri-colouring a triangular grid
1724
190Maximising a weighted product
3579
191Prize Strings
6136
192Best Approximations
1310
193Squarefree Numbers
2749
194Coloured Configurations
1139
195Inscribed circles of triangles with one angle of 60 degrees
1128
196Prime triplets
2130
197Investigating the behaviour of a recursively defined sequence
4290
198Ambiguous Numbers
905
199Iterative Circle Packing
1588
200Find the 200th prime-proof sqube containing the contiguous sub-string "200"
1953