No, thats not it, thanks anyway. It involved adding my carbs, dividing by 10 to ascertain how much insulin to inject. I think he was telling me how much insulin to take if I recorded a high reading on my meter. For example, if my carb intake was 60, I would need 6 of insulin. But if my blood reading was high at , say, 15, I would need more insulin. Thats where the '3' came into the equation, but I just cannot recall what he meant! In future, I will write everything down.