N. V. Williams
It has been said that "behind every great computer there is a great memory". As with most sayings, of course, this is not the whole story.
M. Greening
As will be known, when we write we are expressing the fact that both 12 and 7 have the same remainder when divided by 5.
J141 The real numbers and are such that
J131 (i) How many lines equidistant from three given points can be drawn in the plane?
J. Blatt
Early in the 17th century, Johannes Kepler established, from actual observations of the positions of the planets in the sky, three laws of planetary motion.
x and y are unequal positive integers. Prove that xy does not divide x^2 +y^2$.
"Murgatroyd's Mind-stretchers" by J. and F. Pinkney
Suppose you have two glasses; one contains water and the other contains the same amount of cordial.
J151 (i) Prove that if
J141 The real numbers and
Peter Donovan
This is an account of some elementary aspects of the subject known as "algebraic topology". It investigates the placing of nets on surfaces and Euler characteristics.
Richard Jermyn
This machine is easily constructed from scrap material, using simple tools.
Despite appearances, the following subtraction is wrong:
Peter Donovan
The following problem was considered for publication in Parabola, but rejected as the editorial committee could find no reasonable way of solving it.
Malcolm D. Temperly
The following is a poem which describes how to solve the problem of these instantly insane blocks.
M. G. Greening
Man seems to have known of Pythagoras' Theorem since the early days of civilisation, although the Greek geometers were the first to provide a logical proof.
R. James
Since the last Parabola went to print, the following people have submitted answers.
In a certain country the number of boys born is approximately equal to the number of girls born.
While participating in a census, a census-taker arrived at a certain house in a certain street and proceeded to question the woman who answered, as to the number and ages of the occupants.
Essentially this reduces to proving that
"Men of Mathematics Vols 1 & 2" by E.T. Bell.
J161 Find a whole number, N, satisfying the following conditions:
(a) N is the product of exactly four distinct prime numbers.
J151 (i) Prove that if