To solve this problem, start by analyzing the given information. The three numbers are 7R, RS, and RR. Adding these numbers together should equal 117 because each column must satisfy typical addition rules. Begin with the ones column: the digits must add to end with 7. By trial and error with possible values of R and S, we determine that R must be 2. If R is 2, the addition for the tens column checks out, and it adds up correctly to make the whole sum. Hence, if R is 2, S must be 3. Therefore, the value of S is 3.