$ echo 1.2 2.34 + p | dc
3.54

$ echo 1.2 2.34 + 2 / p | dc
1

$ echo 2 k 1.2 2.34 + 2 / p | dc
1.77

Dc  is a reverse-polish desk calculator which supports unlimited pre-
cision arithmetic.  It also allows you to  define  and  call  macros.
Normally  dc  reads from the standard input;

Normally  dc  reads from the standard input; if any command arguments
are given to it, they are filenames, and dc reads  and  executes  the
contents of the files before reading from standard input.

Printing Commands p Prints the value on the top of the stack, without altering the stack. A newline is printed after the value.

n      Prints  the value on the top of the stack, popping it off, and
       does not print a newline after.

Parameters Dc has three parameters that control its operation: the precision, the input radix, and the output radix.

i      Pops the value off the top of the stack and uses it to set the
       input radix.

o      Pops the value off the top of the stack and uses it to set the
       output radix.

k      Pops the value off the top of the stack and uses it to set the
       precision.