Seriously. That was a long way to go to factor out 16^4. And any decent software developer knows that 16^4 is just 2^16 = 65536. I watched the video looking for some fancy way of doing that last multiplication in your head, and came away very disappointed.
It takes this video 7:16 to reach the 16^4 x 15 point. I did that in my head just looking at the thumbnail. Took me slightly longer than that to move from 16^4 to 65536, which yes, as a software engineer, I know it is (16 x 16) x (16 x 16) = 256 x 256 = 65536.
this is a lot of work for people who havent memorized their powers of 2 to 2^20... on seeing the thumbnail i said how can he spend 9 minutes on 1048576-65536?
where is the trick?
16^5 - 16^4 = 16^4(16-1) = 16^5 * 15 = 15 * 16 * 16 * 16 * 16 = 983040 took me 1 min without calc.
Too complicated. Answer is 16^4 x 15 = 65536 x 15 = 983040
Seriously. That was a long way to go to factor out 16^4. And any decent software developer knows that 16^4 is just 2^16 = 65536.
I watched the video looking for some fancy way of doing that last multiplication in your head, and came away very disappointed.
@@rdwells (65536 x 10) + half of that = 983040. Not too hard, but I would need to write it down and probably not be able to do it in my head.
It takes this video 7:16 to reach the 16^4 x 15 point. I did that in my head just looking at the thumbnail. Took me slightly longer than that to move from 16^4 to 65536, which yes, as a software engineer, I know it is (16 x 16) x (16 x 16) = 256 x 256 = 65536.
Eh, why don't you factor out 16^4 at the very beginning!?!?
=100000₁₆-10000₁₆=F0000₁₆
{0+0 ➖ }^1 1^1(x ➖ 1x+1).
1024*64*15=1024*(64*15)=1024*(64*5*3)=1024*(320*3)=1024*960=992^2-32^2=(1000-8)^2-1024=1000000-16000+64-1024=983040
16
this is a lot of work for people who havent memorized their powers of 2 to 2^20... on seeing the thumbnail i said how can he spend 9 minutes on 1048576-65536?
983040 all in my head