NEW YORK, Aug 7 (Reuters) - U.S. stock index futures trimmed losses and Nasdaq futures turned positive on Friday ahead of key monthly jobs data that could provide clues on the direction of the economy.
* S&P 500 index futures were off 0.70 of a point, and below fair value, a formula that evaluates pricing by taking into account interest rates, dividends and time to expiration on the contract. Dow Jones industrial average futures fell 10 points, while Nasdaq 100 futures added 0.75 of a point.