Truth Tables and De Morgan's Rules

Read this chapter, which discusses Boolean variables as used in decision tables. Truth tables are used to collect variables and their values relative to decisions that have to be made within control structures.

4. Conventional Order


Answer:

Operands
Boolean Expression
x < 12
y > 10
x < 12 || y > 10
F
F
F
F
T
T
T
F
T
T
T
T

Conventional Order

Truth tables are usually organized by putting the operands in a conventional order. Following this order helps prevent mistakes. This table follows the conventional order for two operands:

A
B
expression
F
F
-
F
T
-
T
F
-
T
T
-

Here, A and B represent operands. Often these are relational expressions such as x<12.

The conventional order is easy to remember if you think of F as 0 and T as 1. Arrange the rows in ascending numerical order, as follows:

A
B
expression
0
0
-
0
1
-
1
0
-
1
1
-

Courses on digital logic usually use 0 for false and 1 for true and use truth tables such as the above. The conventional order is also used with tables with more than two operands. With three operands, a table has eight rows. With N operands, a table has 2N rows.


Question 4:

Fill the first table with the conventional order of "0" and "1" (think about what should be in each row
before you click the buttons). Do the rows in order, starting with the top. Then fill in the second table
with the conventional order of "T" and "F".


    A        B        C    - - -
-
-
-
-
-
-
-
-

    A        B        C    - - -
-
-
-
-
-
-
-
-