I use a few objects to do that, like so:

...but there's probably some really nifty "if" statement that'll do it in one object.

Wow - a mode argument for the [change] object! Who knew?

Thanks Double_ug - I now have a few abstractions to edit. :-)

Thank you both so much! They work so well for me and work smoothly. Many thanks!

Ask another question，whether there is an object that can output the difference of the number. For example, the first input of 20, output 20, Second input 26, output 6, Third input 14, output 12...and so on

Similar to my first answer...

or

:-)

110.delta :

[t i i b] I ............... X I ............... [i 0] I ............... I [- 0]

That's great. Thank you very much.