There is a five digit number. It has two prime digits (1 is not a prime number).
Third digit is the highest. Second digit is the lowest. First digit is one less than the
third digit. The fifth digit is half of the fourth. The sum of 4th and 5th is less than the
first. Find the number.
Students attend our lectures, not because the mathematics we teach ‘makes lots of fun’ for us, but because they believe they can learn some essential knowledge from us. And each of our young students has only one life to live. We should therefore be a
H. Behnke
"Obvious" is the most dangerous word in mathematics.