Year 1982 - Volume 18
2020 - Present

B.C. Rennie

For hundreds of years, it was accepted in international law that the territorial waters of any country extended three miles from the shore.

Elvin J. Moore

The knapsack problem is a simple example of a type of "integer programming" problem which is frequently met in the field of mathematics known as Operations Research.

The new format of the 4-unit paper contains provisions for a number of harder questions on the 3-unit syllabus, as well as questions on the 4-unit material.

Andrew Jenkins

I have recently discovered a diversion which may be of interest to readers.

Catherine Playoust

We received a letter from Catherine Playoust, aged 12

Q.515 I have two different integers $>1$. I inform Sam and Pam of this fact and I tell Sam the sum of my two numbers and I tell Pam their product. The following dialogue then occurs:

Q.491 Find a four digit number which becomes nine times as large if the order of digits is reversed. that the territorial waters of any country extended three miles from the shore.

A. K. Austin

I was spending the weekend at Woodful Towers when a wealthy old Sir Joshua Woodful was horribly murdered in the library.

E. Szekeres

Transformations is a collective name for several different methods in Geometry.

Suppose we enter a number, $abc$ say, in a calculator and then repeat it to get $abcabc$. Now divide by $13,11$ and $7$ . The calculator will always display the original number $abc$ why?

Q.527 On a sheet of paper we read the following 100 statements:

Q.503 A rectangle 11cms × 7cms is divided by ruled lines into 1cm × 1cm squares, each containing a button.

Gavin Brown

Perhaps the first law of motion should say "what goes up and comes down must have stopped to turn round".

Esther Szekeres

In my previous article about geometrical transformations I have described two methods, namely parallel translation and similarity transformation.

John Loxton

The art of writing secret messages, intelligible to those who are in possession of the key and unintelligible to all others, has been studied for centuries.

Some interesting applications of calculus appeared in the 1981 3 unit and 4 unit papers. Firstly two geometrical extreme value problems:

Q.539 From the set of whole numbers $\left\{0,1,2,\dots ,999999999\right\}$ two are selected at random. What is the probability that they differ by a multiple of 10000?

Q.515 I have two different integers $>1$. I inform Sam and Pam of this fact and I tell Sam the sum of my two numbers and I tell Pam their product. The following dialogue then occurs: