my question is why the price of some crypto from one exchanger to another is different
It's different because it depends on how many people are trading in those exchanges. Coins that are more expensive on binance are caused by traders which makes the volume higher.
And if you'll see on other exchangers that some of them are quite cheap, you better check on how many buy and sell orders are there. When you figured out on how few traders are there, you've got an hint on why they don't have identical pricing.