Here's an example of creating a constraint at the same time as a table:
create table Table1
constraint PK_Table1 primary key(multiplier1, multiplier2),
constraint CHK_Table1_Answer check (answer = multiplier1 * multiplier2),
check (answer / multiplier1 = multiplier2)
Per @Martin Smith's comment, the constraint name is optional. The database will generate a name for the third constraint, like
Constraints that are introduced on their own line can can refer to multiple columns.