Hi,

How does one solve questions like those of memoriad’s mental addition of ten 10-digit numbers?

I searched the forum and it is mostly squaring and multiplication tricks, what about such addition problems?

Does one just brute force it through until they are fast? Or is there tricks to it too?

I searched the web, read Arthur Benjamin’s Secrets of Mental Math book too, but there doesn’t seem to be anything regarding this.

Thank you.