White to play, and mate in two moves.
There are twelve variations in this beautiful problem.
MAGIC MULTIPLICATION
It will interest all who study short cuts and contrivances to know that a novice at arithmetic who has mastered simple addition, and can multiply or divide by 2, but by no higher numbers, can, by using all these methods, multiply any two numbers together easily and accurately.
This is how it is done:—
Write down the numbers, say 53 and 21, divide one of them by 2 as often as possible, omitting remainders, and multiply the other by 2 the same number of times; set these down side by side, as in the instance given below, and wherever there is an even number on the division side, strike out the corresponding number on the multiplication side. Add up what remains on that side, and the sum is done. Thus:—
| 53 | 21) |
| 26 | (42) |
| 13 | 84) |
| 6 | (168) |
| 3 | 336) |
| 1 | 672) |
| 1113) |
which is 53 multiplied by 21.