The odds for Under 3.5 outcome on major betting sites are, on average, 1.14179104477612 with an implied bookmaker probability of 87.58%. Considering that the surebet probability for the Under 3.5 outcome for this Real Oviedo vs Sporting Gijon match is 70.85%, then this bet is not a value bet.

If you play this bet then you lose expected value by -16.73%The expected value for a UNDER 3.5 prediction is denoted as EV(UNDER 3.5) and is calculated by multiplying the amount of stake by the odds and again by the probability of winning then subtracting the result of multiplying the stake and the probability of losing. 

By using 100 as your sample stake, by calculating the EV as explained, we get the expected value for a UNDER 3.5 in this Real Oviedo vs Sporting Gijon match is 51.74 which is positive and therefore a good bet.All 3 major Surebet prediction models have indicated a possible under 3.5 in this Real Oviedo vs Sporting Gijon match. Poisson prediction model shows there is a 76.92% chance for the outcome while the ELO Ratings model shows a 70.91% chance for the same. 

Finally, 64.72% of the Monte Carlo simulation runs for this match resulted in under 3.5. This pretty much consolidates the prediction of a under 3.5 in this game. In as much as Real Oviedo and Sporting Gijon are expected to score some goals in this match, I do not see a situation where they can score more than 3 goals. 

They have proved in the past that they lack the capacity to stage consistent attacks with shots on target against each other. An under 3.5 prediction for this match is just fine.