|Posted: September 24, 2009, 5:37 pm - IP Logged|
ZEN, in english grammar I know what open & closed sentences are. A closed sentence is one that is always true. For example: Three is an odd number. An open sentence can be true or false. For example: Y is a negative number. It depends on the value that we give to Y.
Also a set of #s can be closed under any of the operations such as addition, subtraction, multiplication or division. I believe you only have to use two of the operations above. As in the example in the last link with the 235, perhaps 2+3=5, 5-3=2. By using two of the operations addition & subtraction we still have the same #s left within the set 235. I am not sure about the open example in the last link. ZEN, I could be wrong about the whole thing...but perhaps it may bring us to the right answer!
Here is a link that mentions the terms in wheeling #s, perhaps the posters could give an explanation:
Here is another link where the terms were used briefly with actual #s: