Can you contrive to pass in turn over all these bridges without ever passing over the same one twice?
ARRANGING THE DIGITS
In a school where two boys were taught to think out the bearings of their work, a sharp pupil remarked that 100 is represented on paper by the smallest digit and two cyphers, which are in themselves symbols of nothing. The master, quick to catch any signs of mental activity, took the opportunity to propound to his class the following ingenious puzzle:—How can the sum of 100 be represented exactly in figures and signs by making use of all the nine digits in their reverse order? This is how it is done:—
9 × 8 + 7 + 6 + 5 + 4 + 3 + 2 + 1 = 100.
Another ingenious method of using the nine digits, so that by simple addition they sum up to exactly 100, and each is used once only, is this:—
15 + 36 + 47 = 98 + 2 = 100
Here is another arrangement by which the nine digits written in their inverse order can be made to represent exactly 100:—
98 - 76 + 54 + 3 + 21 = 100.
Here is yet another way of arriving at 100 by using each of the digits, this time with an 0:—