Mathematical Help

[Rob]

hi all,

i need a bit of help with a decimal to binary conversion - cant use a calculator need to do this on paper!

getting stuck on the last bit - and need a guiding hand - anyone help?

[Monster-Mat]

erm where is it...

[Rodders_UK]

happy to help if i can

[Rob]

ok eg converting 327, the way i do it might be a bit wierd.....

327/2=163 163x2=326 remainder =1 ( the remainder gives me the binary)

163/2=81 81x2=162 R=1

81/2=40 40x2=80 R=1

40/2=20 20x2=40 R=0

20/2=10 10x2=20 R=0

10/2=5 5x2=10 R=0

5/2=2 2x2=4 R=1

who else knows how to do it this way? if so can u finish the conversion?

[aido]

I do it a bit different fella....

Basically, I set up a grid like this:

Now basically make each bit one starting from the left, if they add up to more than the number you're after you know to leave that number as a 0, so we end up with something like this (I didn't start at 512 as we already know that is too big)

256 128  64   32   16    8    4    2    1

1    0    0    0    0    0    0    0    0 = 256 - ok
1    1    0    0    0    0    0    0    0 = 384 - too much
1    0    1    0    0    0    0    0    0 = 320 - ok
1    0    1    1    0    0    0    0    0 = 352 - too much
1    0    1    0    1    0    0    0    0 = 336 - too much
1    0    1    0    0    1    0    0    0 = 328 - too much
1    0    1    0    0    0    1    0    0 = 324 - ok
1    0    1    0    0    0    1    1    0 = 326 - ok
1    0    1    0    0    0    1    1    1 = 327 - bingo :)

So the binary value you're after is 101000111 - is that ok?

Does that make sense?

My MSN is fecked pal

[MacRS200]

Binary is nursery stuff try Hex code :D

[Mark D]

You were nearly there - just keep going.

To convert numbers from decimal to binary requires successive division.

To manually convert from a decimal to a binary number, start with the decimal number and begin dividing by the binary number base (base "two"). For each step the division results in a remainder of 1, use '1' in that position of the binary number. When the division results in a remainder of 0 instead, use '0' in that position. Stop when the division results in a value of 0. The resulting binary numbers are ordered from right to left.

For example, the decimal number 327 converts to binary as follows:

327 / 2 = 163 remainder 1

163 / 2 = 81 remainder 1

81 / 2 = 40 remainder 1

40 / 2 = 20 remainder 0

20 / 2 = 10 remainder 0

10 / 2 = 5 remainder 0

5 / 2 = 2 remainder 1

2 / 2 = 1 remainder 0

1 / 2 = 0 remainder 1

Therefore the decimal number 327 equals the binary number 101000111.

[Rob]

hi all thanks for the replies - i had another look at the working this morning and realised i was being a numpty and was looking at the wrong figure on the last bit! all sorted now .

ta rob.

[eXOBeX]

For Windoze users:-

Start -> Run

calc

View -> Scientific

[Rob]

For Windoze users:-

Start -> Run

calc

View -> Scientific

←

cant take my computer or even allowed to use a calc in my exams !

[eXOBeX]

Aaah, makes sense now.

Mark D's "successive division" method isn't what I would've used, but looks like a good method. Just get a few practice runs in first to get used to it (checking your answers with Calc or similar) before the exam!

[aido]

Just seen your text Rob, congrats on passing the exam with 95% :D

[Rob]

thanks mate, there was only 1 binary Q and it was "what is 1101" !

roll on the next one i suppose

[aido]

Bugger me after all that too :P

Least you know how to count in binary now, there's a house down here and they have the house number as binary, I thought it was quite clever but I'm just a geek

[Mark D]

Bugger me after all that too :P

Least you know how to count in binary now, there's a house down here and they have the house number as binary, I thought it was quite clever but I'm just a geek

←

it's your house - isn't it? :P