There’s 5.5B shares roughly on issue and say the price is 0.001 a share which makes 5.5bX0.001 = a market cap of 5.5m say if the share price doubled (in which is did on Friday) to 0.002 a share then it would be 5.5Bx0.002 which equals 11m market cap, so the market cap equals the share price multiplied by the number of shares on issue! If this is the answer you’re after