basicily you grt the first number (1) and then times it by the second number (1).
For example................
3 x 4 = 12
BECAUSE 3 + 3 + 3 + 3 = 12
In general, any number times one is the number, because you are considering that there is just one number to add to, well, no other numbers.
Thus, the answer, since you are multiplying one by one, is one.