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Problems


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