Illustration of assignment statements:
At that point, if the expression mynum 3 is entered, the default variable ans is used as the result of this expression is not assigned to a variable. Therefore, the value of ans becomes 10 but mynum is unaffected (it is still 7). Note that merely typing the name of a variable will show its value.
>> mynum + 3
ans =
10
>> mynum
mynum =
7