Search ProblemsRSS Feed
Cache update: 57 minutes

Problems Archives

The problems archives table shows problems 1 to 641. 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
4561
152Writing 1/2 as a sum of inverse squares
2121
153Investigating Gaussian Integers
2083
154Exploring Pascal's pyramid
2116
155Counting Capacitor Circuits
2912
156Counting Digits
1921
157Solving the diophantine equation 1/a+1/b= p/10n
2159
158Exploring strings for which only one character comes lexicographically after its neighbour to the left
2980
159Digital root sums of factorisations
2687
160Factorial trailing digits
2837
161Triominoes
1663
162Hexadecimal numbers
4530
163Cross-hatched triangles
1459
164Numbers for which no three consecutive digits have a sum greater than a given value
4798
165Intersections
2094
166Criss Cross
3347
167Investigating Ulam sequences
1359
168Number Rotations
2155
169Exploring the number of different ways a number can be expressed as a sum of powers of 2
4239
170Find the largest 0 to 9 pandigital that can be formed by concatenating products
1580
171Finding numbers for which the sum of the squares of the digits is a square
2234
172Investigating numbers with few repeated digits
3133
173Using up to one million tiles how many different "hollow" square laminae can be formed?
7816
174Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements
4998
175Fractions involving the number of different ways a number can be expressed as a sum of powers of 2
1447
176Right-angled triangles that share a cathetus
1546
177Integer angled Quadrilaterals
1010
178Step Numbers
2772
179Consecutive positive divisors
9636
180Rational zeros of a function of three variables
1259
181Investigating in how many ways objects of two different colours can be grouped
1618
182RSA encryption
2153
183Maximum product of parts
3967
184Triangles containing the origin
1291
185Number Mind
2577
186Connectedness of a network
2346
187Semiprimes
9638
188The hyperexponentiation of a number
5501
189Tri-colouring a triangular grid
1682
190Maximising a weighted product
3500
191Prize Strings
6013
192Best Approximations
1276
193Squarefree Numbers
2680
194Coloured Configurations
1116
195Inscribed circles of triangles with one angle of 60 degrees
1090
196Prime triplets
2077
197Investigating the behaviour of a recursively defined sequence
4220
198Ambiguous Numbers
885
199Iterative Circle Packing
1545
200Find the 200th prime-proof sqube containing the contiguous sub-string "200"
1894