$SPX so far day low = yesterday's close
1/2 hour trading
day high = 3066.76√ = 55.37833511
-day low = 3055.85√ = 55.27974312
= 0.09859199

+ 55.37833511 = 55.4769271 *2
= 3077.68(944)

OR 
55.27974312 - 0.09859199
= 55.18115113 *2
= 3044.95(944) https://t.co/11fnlvogf5