.   ?   D.   U.   UD.

. ( n ---)

Remove the value at the top of the stack and display it as a signed single precision integer.

1 .                     \ display 1
1 2 .                   \ display 2  leave 1 on stack
1 2 + .                 \ display 3  addition 1 and 2, leave nothing on the stack
6 3  * .                \ display 18
7 3  * 6 3 * + .        \ display 39 operation (7*3)+(6*3)

? ( addr -- )

Displays the content of any variable or address.

D. ( d ---)

Removes the double value from the top of the stack and displays it as a signed double precision integer.

1. D.                   \ display 1
1. 2. D.                \ display 2  leave 1 on the stack
1. 2. D+ D.             \ display 3  add 1 and 2, leave nothing on the stack

U. ( n ---)

Removes the value from the top of the stack and displays it as an unsigned single precision integer.

1 U.                    \ display 1
-1 U.                   \ display 65535

UD. ( n ---)

Removes the value from the top of the stack and displays it as an unsigned double precision integer.

1. UD.                  \ display 1
1. 2. UD.               \ display 2  leave 1 on the stack
1. 2. D+ UD.            \ display 3  add 1 and 2, leave nothing on the stack