The way to write four sevens with simple
arithmetical signs so that they represent 100 is as follows:
7/.7×7/.7 = 100.
Of course the fraction, 7 over decimal 7, equals 7
divided by 7/10, which
is the same as 70 divided by 7, or 10.
Then 10 multiplied by 10 is 100, and there you are!
It will be seen that this solution applies equally
to any number whatever that you may substitute for 7.