I have researched and written about methods of mental calculation over the years, and I’m often surprised at the ingenuity evident in the mathematical methods developed specifically for it. Based on my Lightning Calculator series of essays here, I’ve created a new 2011 calendar titled Lightning Calculation. It’s a unique, interactive calendar for developing abilities in mental calculation. You can download a free PDF file for printing on your computer, or if you prefer, order it for delivery through Lulu.com. I also think it might be a nice thing to make as a Christmas gift for someone interested in this sort of thing, or for displaying in a math classroom.
NOTE: If you choose to have the calendar professionally printed by Lulu.com rather than on your own printer, through December 31 you can enter the code REMARKABLEYEAR305 at checkout for 20% off the price of $17.60. The Lulu site is also posting daily coupon codes in December here.
A different field of mental calculation is treated each month in this calendar, from 2-digit multiplication to square roots to factoring to logarithms and more. The upper half of each calendar page describes methods that can be used to solve problems of that month, and the lower half offers opportunities to test yourself and practice these techniques daily using the actual dates shown in the calendar. Of course, you should feel free to try all the dates at once, or bounce around between months, or do whatever you want. After all, this is all for fun!
Every month includes a legend that describes how the dates are used in the calculations. In nearly all cases the answers are provided right in the calendar itself, printed in number boxes connecting the dates involved in the calculation but small enough that they are not visible from a distance. Every day starting in February also poses a day-date calculation. In all, there are nearly 4000 exercises in mental calculation embedded in this calendar!
The calendar is available for downloading and printing at the link below. The format is two-sided 8-1/2″ x 11″ sheets of paper printed in landscape mode that can be connected at their edge. This could be printed to fit on A4 or other sizes, I’m sure. I recommend printing it on colored paper; although it looks fine on white paper, the color scheme is really designed for a light beige or ivory paper and it looks so much more professional when it’s printed on paper of some color. In the past I’ve had a local office shop (Kinko’s FedEx) add clear plastic sheets to the front and back and install a spiral wire (a 60-second job that costs $5). Drilling a hole in the center along the top to hang it completes the calendar. Using 3 rings through punched holes along the top may be a cheaper option.
Alternatively, and in response to comments on last year’s calendar, it is available for ordering from Lulu.com if you prefer. The downloadable PDF file below has all the resolution of the Lulu.com version—the only difference between them is that the Lulu version has a light beige/ivory background that I did not include in the downloaded PDF to save printer ink. The photo above is of the Lulu.com version, which is beautifully printed. The calendar is listed on the site as a coil-bound book that you turn sideways to use (it’s not in the calendar category), and you will have to punch or drill a hole in it to hang it on a hanger.
Small images of the front and back and each page of the calendar are shown below. These provide only a rough idea of the content, but if you think you might be interested, the complete PDF file is just over 10MB, so it is easily downloaded and viewed at full resolution. The last page is flipped upside down in order that the back of the calendar has the same orientation as the front cover.
The PDF of the calendar for personal printing is found here.
The calendar on Lulu.com is found here.
Hope you like it. Have a happy 2011!