Tell a person to set down a sum of money less than £12, in which
the pounds exceed the pence; next to reverse this amount, making
pence pounds, etc., and to subtract the one from the other, then
set beneath the result itself reversed, adding the last two lines
together, when you will tell him the result, which will _always_
be £12 18s. 11d.
Example: £10 8 7
7 8 10
--------
2 19 9
9 19 2
--------
£12 18 11
If the performer be blindfolded the trick looks very mystifying;
he should not, however, repeat it, for many would soon discover
the secret, but as the peculiarity is not confined to money, other
illustrations can be given if required--for instance--if a number of
yds., ft. and inches (less than 12 yds.) be operated on, the final
answer will always be 12 yds. 1 ft. 11 inches; and if a number of
cwts., qrs. and lbs. (less than 28 cwts.) be chosen, the answer will
always be 28 cwts. 2 qrs. 27 lbs.
“Girls” and “Boys.”
At a school examination, the inspector set the girls to write an
essay on “Boys” and the boys to write one on “Girls.”