Posted by permission of Michael Reid. Enjoy!
New Year’s Greetings!
Here are some fun puzzles to start the year.
1. Substitute the numbers 1, 2, … , 9 for the letters
a, b, … , i in the expression
to get 2020.
2. Use the digits 1, 2, … , 9 in order, and any of the usual
arithmetic operations and parentheses to get a number that is
as close as possible to, but not exactly equal to 2020.
3. Express 2019/2020 as a sum of distinct Egyptian fractions,
i.e. for integers
(but 202049 is not square).
5. Make a 4×4 matrix of single-digit integers (0-9) with digits
2, 0, 2, 0 on the main diagonal, and having determinant 2020.
Is it possible to do it with a symmetric matrix?
If you liked this one, check out other puzzles ont this blog tagged with “Michael Reid”.