hi!
I wanted to share with people that are interested in mental calculation in a technique that I recently across when I was trying calculate using the palace of memory and it cross to my head the idea of changing the colors of the number with the intention of make them more easy to visualize them in my head (using the memory palace). Actually I am just change the colors of the numbers but in a week I will make a list of the numbers 09 and associate them with a color and after that make the same with the numbers 1019 until arrive the number 100.
I was expecting for more ideas of you guys, for make the numbers more memorable with the mix of more techniques.
Now I will go with the technique…

Visualize a board in front of you in a room of a palace of memory.

Make a multiplication. Per example: 12x14.
First: multiply 4x2, that is 8.
Second: multiply 4x1 and 2x1 after that plus them and it will be 6.
Third: multiply 1x1 that will be 1.
So the result its 168.
However, it is not easy sometimes remember the multiplication while you are doing at the same time that the reason about decide the colors of the numbers and I think that change the size of the number it will also work.