# Alu Worksheet question Classic List Threaded 7 messages Open this post in threaded view
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## Alu Worksheet question

 This post was updated on . Hello, So i am now at point 4 in the Alu Worksheet where f(x) = x The problem arrises at F. where it is false and so i have to do the first multiplication. So i am multiplying 0100 x 1111 = 0111100.This is a signed number so 0 goes away but indicates that the number is positive so we have 111100 right? Also this is a confusing answer because it has more bits than 4 and because i know we work in 4bit system i wonder if this answer is correct. The previous exercises always got me no=f(x,y) but this doesn't. What am i missing here?
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## Re: Alu Worksheet question

 Ok so i just finished the whole worksheet besides line 4,5,6,7 and the last one. 4,5,6,7 all have multiplication at f and the out =/= f(x,y) And the last point i don't understand x|y = x or y wich means x+y , if so , here i also get a wrong answer.
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## Re: Alu Worksheet question

 Administrator There is no multiplication in the ALU. When f=0 the ALU does binary AND which uses the symbol '&' in the worksheet. When f=1 the ALU does arithmetic ADD which uses the symbol '+' in the worksheet. The symbol '|' means binary OR. '+' in this worksheet always means ADD.
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## Re: Alu Worksheet question

 This post was updated on . Thank you very much, i have successfully finished all of them now !!!
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## Re: Alu Worksheet question

 Administrator You should get 1111. ``` 1111 OR 1010 ---- 1111 ```