multiply two variables to create a total score variable

Creating a risk assessment and need to do severity x likelihood = score

Current set up (each section, of which there are 36 sections)

• users select drop down risk severity: “very low, low, medium, high, very high” with 1-5 score attached to each
• This total has a variable output “Var_1”
• users then select drop risk likelihood: “very low, low, medium, high, very high” with 1-5 score attached to each
• This total has a variable output “Var_2”

Then i get stuck, what i want to do then is

• I need to multiply “Var_1” x “Var_2” and output score to new variable “Var_3”
• I then need to recall this variable (Var_3) to tell users their risk score
• The user then needs to mitigate or justify the risk in long text format
• I then need to recall “Var_3” again, and ask the user if their mitigation or justification is strong enough to reduce this score to an acceptable level by asking them to input a new score which I want to become a new variable, “Var_4”

There are 36 separate risks, at the end i want to call all the Var_4 for each section (which will be “Var_8, Var_12, Var_16, etc.) and give them an overall score for each section. It would be amazing to then give an overall score in “Var_total” 

I may well be going about this wrong, the main problem to solve is severity x likelihood = score, however if someone has a smarter, more logical and lower effort approach I would be really grateful!