Puzzles
10 December
This number is divisible by 2. One more than this number is divisible by 3. Two more than this number is divisible by 5. Three more than this number is divisible by 7. Four more than this number is divisible by 11. Five more than this number is divisible by 13.
9 December
You start at A and are allowed to move either to the right or upwards.
How many different routes are there to get from A to B?
8 December
What is the largest number of factors which a number less than a million has?
7 December
In September, my puzzle appeared as Alex Bellos's Monday Puzzle. The puzzle asked what the highest rugby score was which can only be made with one combination of kicks, tries and converted tries.
What is the highest rugby score which can be made with 101 different combinations of kicks, tries and converted tries?
6 December
Put the digits 1 to 9 (using each digit once) in the boxes so that the three digit numbers formed (reading left to right and top to bottom) have the desired properties written by their rows and columns.
multiple of 5 | |||
multiple of 7 | |||
cube number | |||
multiple of 9 | multiple of 3 | multiple of 4 |
Today's number is the multiple of 5 formed in the first row.
5 December
How many different triangles are there with a perimeter of 100 and each side
having an integer length?
(different = not rotations or reflections)
4 December
Put the digits 1 to 9 (using each digit exactly once) in the boxes so that the sums reading across and down are correct. The sums should be read left to right and top to bottom ignoring the usual order of operations. For example, 4+3×2 is 14, not 10.
- | + | = -4 | |||
+ | + | + | |||
- | ÷ | = -1 | |||
- | ÷ | × | |||
- | × | = -30 | |||
= 0 | = 2 | = 54 |
The answer is the product of the digits in the red boxes.
3 December
In August, I wrote about MENACE, a machine learning robot built from matchboxes which plays noughts and crosses. How many matchboxes are needed to build MENACE?