Are cryptocurrency prices equal in value across all trading platforms at the same time? And when a strong rise or sharp decline occurs, does it happen on all trading platforms?

Certainly, cryptocurrency prices are not exactly the same across all trading platforms at the same time. There are several reasons for this:

Difference in supply and demand: Each trading platform has a different set of buyers and sellers, leading to slight variations in the supply and demand for the cryptocurrency. This directly affects the price traded on that platform.

Trading liquidity: Trading liquidity varies from one platform to another. Platforms with high liquidity experience less severe price fluctuations, while platforms with low liquidity may see larger price movements due to smaller trading volumes.

Trading fees: Trading fees differ between platforms.

As for strong rises and sharp declines:

When a strong rise or sharp decline occurs in the price of a specific cryptocurrency, it usually happens on most or all trading platforms at approximately the same time.