Happy 40th Birthday HP-65

First pocket programmable calculator (Photo credit: Wikipedia)

Two years ago we celebrated the fortieth birthday of the HP-35, the first mass-produced, pocket-sized, scientific calculator.

Today marks the fortieth birthday of its younger sibling, the HP-65, released on 17 January 1974. This was the world's first programmable calculator.

The first programmable calculators were introduced in the mid-1960s by Mathatronics and Casio, but these machines were very heavy and expensive.

So the miniaturisation involved in the HP-65 was a breakthrough. Bill Hewlett is supposed to have insisted that the calculator should fit in his shirt pocket and this was partly achieved with the tapered body.

The HP-65 had a capacity of 100 instructions, and could store and retrieve programs with a built-in magnetic card reader. The magnetic program cards were fed in at the thick end of the calculator under the LED display.

Examples for programs provided with the calculator included algorithms for hundreds of applications, including the solutions of differential equations, stock price estimation and statistical functions.

Pi Day Live

Thursday is the annual Pi Day (because Americans would write the date 3.14).


This year, Marcus du Sautoy is hosting Pi Day Live. It's a free interactive online event that is open to all.

The number pi has intrigued mathematicians throughout the ages and this fascination has shown no sign of stopping. In recent times mathematicians have employed super-computers to calculate pi to over a trillion decimal places.

In Pi Day Live, Marcus du Sautoy will be asking whether the techniques used by the ancients to calculate pi can still be used today. And if so, which ones are best? As a part of the interactive audience, you will be a part of answering these questions and more.

To take part, visit the event's online lecture theatre, or go to the event's big screen to watch online. All you need is access to YouTube to get involved.

Make a Great Resource and Win a Great Prize

MEI (Mathematics in Education and Industry) and Tarquin Books are joining forces to offer an annual prize to post-16 maths students.

Entrants must design an electronic resource - e.g. Geogebra file, Excel spreadsheet, a video, etc. - that communicates the mathematical ideas needed to solve a practical problem of some kind. These mathematical ideas used should be relevant to A-Level Mathematics or Further Mathematics A-Level, or to some equivalent qualification. Your entry could be designed by you individually, or it could be a collaboration between a group of students.

Entries to the competition could also form the basis for an Extended Project Qualification.

The winner will receive books to the value of £100 and Tarquin Books will also donate £400 worth of books or materials to the winners’ school or college.

To register your interest in the competition, follow the Prizes link on the Tarquin website. The closing date for entries is 30 April 2012 and the winner will be announced by 31 May 2012. For further information email Andrew Griffin at Tarquin.