In my head, what I do in the end is 9x27 = 3^2 * 3^3 = 3^5 = 243 ('everybody' knows that, because of 7^3 = 343)
And 27 x 16 ends up being (32 - 5) x 16 = 512 - 80 = 432.
And yes, I could be way faster at mental arithmetic if I just did the calculations instead of switching to cuter approaches halfway through all the time.
And 27 x 16 ends up being (32 - 5) x 16 = 512 - 80 = 432.
And yes, I could be way faster at mental arithmetic if I just did the calculations instead of switching to cuter approaches halfway through all the time.