The set of natural numbers is closed under :
AAddition and multiplication
BAddition and subtraction
CAddition and division
DMultiplication and subtraction
AAddition and multiplication
BAddition and subtraction
CAddition and division
DMultiplication and subtraction
Related Questions:
$$Find the number of zeros at the right end of
$12^5\times25^2\times8^3\times35^2\times14^3$