To calculate the approximate price range of fixed options, you can use the following methods:
Intrinsic value calculation:
Since the exercise price of an equal option is equal to the price of the underlying asset, its intrinsic value is theoretically zero (but it may actually be slightly biased due to rounding and other reasons).
For call options: intrinsic value = maximum value (0, underlying asset price-exercise price)
For put options: intrinsic value = maximum value (0, strike price-underlying asset price)
Time value considerations:
Although it is mentioned in the title that it will expire soon, there is no need to think too much about the time value, but in fact, even if it is the doomsday round, the option will still have a little residual time value. This time value is usually small, but it may still affect the option price for very short-term options.
Volatility and option price;
Volatility is an important factor affecting the option price. High volatility usually increases the price of options (whether bullish or bearish), because it increases the possibility that the price of the underlying assets will change greatly before maturity.
In the case of the doomsday wheel, if the volatility is unusually high, even if the time value is small, the option price may be high because of the volatility.
Greek value of options:
Greek values (such as Delta, Gamma, Vega, etc. ) can help you understand the sensitivity of option prices to various factors. In particular, Delta represents the expected change of option price when the price of the underlying asset changes by one unit.
For flat options, the Delta value is usually close to 0.5 (for call options) or -0.5 (for put options), which means that small changes in the underlying asset price may not have much impact on the option price.
Rule of thumb and market observation;
Your "average value is mainly around 100" may be based on the empirical observation of a specific market or a specific variety. This rule of thumb may apply to some market conditions, but not necessarily to all situations.
Market sentiment and liquidity will also affect the option price. For example, when the market panics or is extremely optimistic, the option price may deviate from the theoretical value.
Trading strategy and profit:
For flat options, you can set the take profit point according to the intrinsic value and the remaining time value. If the option price is higher than this take profit point, it may mean that the market's expectation of the option is too high, or there are other unknown risk factors.
In addition, the take profit strategy can be adjusted according to the Greek value. For example, if the Delta value approaches 1 or-1 quickly, it may mean that the option is getting closer to the real value or imaginary value, and you may need to consider adjusting the take profit point.
Please note that the above methods provide a theoretical framework and reference ideas, and the actual application needs to be combined with specific market conditions, trading strategies and risk management requirements to make decisions.