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Problems Archives

The problems archives table shows problems 1 to 739. 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
5258
152Writing 1/2 as a sum of inverse squares
2523
153Investigating Gaussian Integers
2469
154Exploring Pascal's pyramid
2483
155Counting Capacitor Circuits
3386
156Counting Digits
2274
157Solving the diophantine equation 1/a+1/b= p/10n
2544
158Exploring strings for which only one character comes lexicographically after its neighbour to the left
3424
159Digital root sums of factorisations
3125
160Factorial trailing digits
3313
161Triominoes
1973
162Hexadecimal numbers
5108
163Cross-hatched triangles
1693
164Numbers for which no three consecutive digits have a sum greater than a given value
5479
165Intersections
2423
166Criss Cross
3864
167Investigating Ulam sequences
1570
168Number Rotations
2503
169Exploring the number of different ways a number can be expressed as a sum of powers of 2
4789
170Find the largest 0 to 9 pandigital that can be formed by concatenating products
1856
171Finding numbers for which the sum of the squares of the digits is a square
2594
172Investigating numbers with few repeated digits
3595
173Using up to one million tiles how many different "hollow" square laminae can be formed?
8750
174Counting the number of "hollow" square laminae that can form one, two, three, ... distinct arrangements
5596
175Fractions involving the number of different ways a number can be expressed as a sum of powers of 2
1649
176Right-angled triangles that share a cathetus
1778
177Integer angled Quadrilaterals
1189
178Step Numbers
3208
179Consecutive positive divisors
10837
180Rational zeros of a function of three variables
1471
181Investigating in how many ways objects of two different colours can be grouped
1859
182RSA encryption
2466
183Maximum product of parts
4470
184Triangles containing the origin
1521
185Number Mind
2934
186Connectedness of a network
2689
187Semiprimes
10762
188The hyperexponentiation of a number
6123
189Tri-colouring a triangular grid
1917
190Maximising a weighted product
3952
191Prize Strings
6755
192Best Approximations
1492
193Squarefree Numbers
3092
194Coloured Configurations
1298
195Inscribed circles of triangles with one angle of 60 degrees
1289
196Prime triplets
2406
197Investigating the behaviour of a recursively defined sequence
4686
198Ambiguous Numbers
1039
199Iterative Circle Packing
1818
200Find the 200th prime-proof sqube containing the contiguous sub-string "200"
2210