Mental Arithmetic Series So Far - Still To Come

We've had a look at some of the simple Trachtenberg techniques so far, and applied them for the simplest of multiplications, beginning with multiplication by 11, then 12, and then 6.

The techniques so far covered include adding the number in a column to its neighbour on the right, doubling a digit, halving a digit down, and adding 5 to a digit if it is odd.

The next post in this series, 003, will go through multiplication by 5 and by 7, with exercises and some number tables for you to try out.

And then I will summarise what you have done so far, by reprising the rules for multiplications by the numbers thus far covered: 5, 6, 7, 11 and 12.

There'll be a second round of techniques, involving 9's complements and 10s' complements, and an introduction to a Vedic Mathematics sutra, "All From 9 And The Last From 10," but between 003 and then will be an interlude where I will show you one of my favourite tricks.

Look for further posts in this series soon.

9/13 - Moonbase Alpha Breakaway - LEST WE FORGET

On this day, 11 years ago, the Moon was knocked out of Earth's orbit and sent flying off into deep space when Nuclear Waste Disposal Area 2 blew up.

Let us hold a minute's silence in memory of the brave men, women and female alien shapeshifters of Moonbase Alpha, and a reminder of why we subsequently went to war with the Dorcons.

Never again.