| miles | furlongs, | rods, | yards, | feet, | inches. | |
| From | 1 | 0 | 0 | 0 | 0 | 0 |
| Take | 0 | 7 | 39 | 5 | 1 | 5 |
| 0 | 0 | 0 | 0 | 0 | 1 |
In this problem, instead of borrowing 1 foot, we borrow 1/2 a foot = 6 inches, from which we take 5 inches, and 1 remains; we then carry 1/2 to 1, and borrowing 1/2 a yard = 1 1/2 feet, we have 1 1/2 from 1 1/2 = 0, and afterwards proceed as usual.
THE EXPUNGED FIGURE.
In the first place desire a person to write down secretly, in a line, any number of figures he may choose, and add them together as units; having done this, tell him to subtract that sum from the line of figures originally set down; then desire him to strike out any figure he pleases, and add the remaining figures in the line together as units, (as in the first instance,) and inform you of the result, when you will tell him the figure he has struck out.
76542-24
24
———
76518
Suppose, for example, the figures put down are 76542; these, added together, as units, make a total of 24: deduct 24 from the first line, and 76518 remain; if 5, the center figure be struck out, the total will be 22. If 8, the first figure be struck out, 19 will be the total.
In order to ascertain which figure has been struck out, you make a mental sum one multiple of 9 higher than the total given. If 22 be given as the total, then 3 times 9 are 27, and 22 from 27 show that 5 was struck out. If 19 be given, that sum deducted from 27 shows 8.
Should the total be equal multiplies of 9, as 18, 27, 36, then 9 has been expunged.
With very little practice any person may perform this with rapidity, it is therefore needless to give any further examples. The only way in which a person can fail in solving this riddle is, when either the number 9 or a cipher is struck out, as it then becomes impossible to tell which of the two it is, the sum of the figure in the line being an even number of nines in both cases.
THE MYSTERIOUS ADDITION.