# Does this question really require such a long truth table?

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## 3 Replies - 551 Views - Last Post: 30 April 2017 - 06:00 AM

### #1 hhjkkh20

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# Does this question really require such a long truth table?

Posted 29 April 2017 - 04:38 PM

I started doing the table but i realised there would be a tonne of different possibilities, a stupid amount that makes me feel like i dont understand the question. Before you say, i understand that its only 3 numbers of each 4 bit binary number. Thanks for the help in advance

Here is the question:

A group of three binary inputs is used to represent the values 0 – 7. For each of the values 2, 5 or 7 the output will be TRUE, otherwise the output will be false.

Construct the truth table.

Here is the link to the table i have started.

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## Replies To: Does this question really require such a long truth table?

### #2 jon.kiparsky

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## Re: Does this question really require such a long truth table?

Posted 29 April 2017 - 05:53 PM

Please post the table as text (preferably using the [code] tags or a monospaced font for readability)

### #3 r.stiltskin

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## Re: Does this question really require such a long truth table?

Posted 29 April 2017 - 06:24 PM

hhjkkh20, on 29 April 2017 - 07:38 PM, said:

Before you say, i understand that its only 3 numbers of each 4 bit binary number.

Why "4 bit" binary number? You only need 3 bits to represent 0-7, so why would you need any more than that in the truth table?

### #4 sepp2k

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## Re: Does this question really require such a long truth table?

Posted 30 April 2017 - 06:00 AM

hhjkkh20, on 30 April 2017 - 01:38 AM, said:

A group of three binary inputs is used to represent the values 0 – 7.

This doesn't mean that you have three numbers between 0 and 7. It means you have three bits ("binary inputs") that make up a single number between 0 and 7.