With Bitcoin, staging a 51% attack on the network is seemingly unlikely, simply due to the size of the network and its hash rate. One estimate puts the cost of running a 51% attack on Bitcoin at just over 15 billion USD.
How do you count Bitcoins?
The unit of measurement of BTC is ‘Satoshi’, which was named in honour of the founder of Bitcoin, Satoshi Nakamoto. A satoshi represents the smallest unit of a Bitcoin and there are 100,000,000 satoshis per one bitcoin. Assume that you have bought a coin that is worth $0.20 each, and it doubled in value to $0.40.