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Convert 729 from base 10 to base 2.

 May 1, 2020
 #1
avatar+299 
+1

Binary is fun.

 

512      256      128      64       32       16       8       4       2       1       
1011011001

 

The answer is 1011011001 :D

 

oops forgot to log in, I'm CentsLord xD

 May 1, 2020
edited by Guest  May 1, 2020
edited by CentsLord  May 1, 2020
 #2
avatar+111360 
+3

2^9  =  512

 

Subtract  this from  729  = 217

 

2^7 = 128

 

Subtract this from 217  =  89

 

2^6  =  64

 

Subtract this from  89  =  25

 

2^4  = 16 

 

Subtract this from 25  = 9

 

2^3  =  8

 

Subtract this from 9  = 1

 

2^0  = 1

 

So  writing  backwards we have

 

Powers of 2       0 1 2  3  4   5  6  7  8  9

                          1 0 0  1  1   0  1 1   0  1

 

Reverse the part in red

 

72910 = 10110110012

 

cool cool cool

 May 1, 2020
 #3
avatar+299 
+1

Cool! I never knew there was a method to it - Always just used intuition :)

CentsLord  May 1, 2020
 #4
avatar+111360 
+1

Actually, CentsLord....I seem to recall  that there is an easier way to do this, but I don't remember the exact method....

 

 

 

cool cool cool

CPhill  May 1, 2020
 #5
avatar+928 
+1

I've seen the method CPhill used before...My maths teacher called it the "Greedy Method" which means that you take the highest power of 2 from the number and subtract. Then you subtract the largest power of two from that. So on and so forth...

 

I don't recall an easier method but I would like to learn it!

HELPMEEEEEEEEEEEEE  May 1, 2020
 #6
avatar+299 
+1

o _ O I have realized I've been doing that without realizing it! :D

CentsLord  May 2, 2020

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