Symbols are
a concise
way of giving
lengthy
instructions
related to
numbers and
logic.
Symbols are
a communication
tool. Symbols
are used to
eliminate the
need to write
long, plain
language
instructions to
describe
calculations
and other
processes.
For example, a
single symbol
stands for the
entire process
for addition.
The familiar
plus sign
eliminates the
need for a long
written
explanation of
what addition
means and how
to accomplish
it.
The same
symbols are
used worldwide
. . .
The symbols
used in
mathematics are
universal.
The same math
symbols are
used throughout
the civilized
world. In most
cases each
symbol gives
the same clear,
precise meaning
to every
reader,
regardless of
the language
they speak.
The most
valuable,
most
frequently used
Symbols in
mathematics . .
.
The most
important, most
frequently used
Symbols for
Set
Notation
are listed
below.
Math
Symbol for
the
"Union
of
Sets"

D
A
means
combine
Set
"D"
with Set
"A":
(1)
Every
element
(without
exception)
contained in
Set
"D"
is combined
with every
element present
in Set
"A".
And .
. .
(2)
If Set
"D"
and Set
"A"
have any
elements which
are the same,
that element is
listed only
once in the
combined
set.
Example 1:
, Set
A:
A =
{ a, b, c,
d
}
Set
D: D
=
{ e, f
}
. . . The
"Union"
of Set
"D"
and Set
"A"
produces a
new set
which
contains
all the
elements
of both
sets:
a, b,
c, d, e,
f
D
A
= {a, b,
c, d, e,
f}
Example 2:
, Set
B:
B =
{
1, 3, 9,
11
, 13,
14}
Set
E:
E =
{
1, 3, 9,
11
}
. . . Both
Set
"E"
and Set
"B"
contain
some of
the same
elements:
1, 3, 9,
11. These
elements
will only
be listed
once in
the new,
combined
set.
E
B
= {1, 3,
9, 11, 13,
14}
Note:
When
both
SETS
contain
the
same
element,
that
element
is
listed
only
once
in
the
new,
combined
set.
Example 3:
, Set
C:
C =
{dog,
horse,
bird,
rabbit,
cat
}
Set
F:
F =
{
cat,
rabbit
}
. . . Both
Set
"F"
and Set
"C"
list the
following
elements
in a
different
order:
rabbit,
cat
C
F
= {dog,
horse,
bird,
rabbit,
cat}
Note:
the
elements
within
a SET
can
be
listed
in
any
order.