a logarithm
A logarithm is the power that 10 has to be raised to get a number. It’s from Greek words meaning ‘reason’ and ‘number’. It’s used in math when you do stuff like population growth.
'The log of 1000 is 3 because 10^3 = 1000.'
'Log of 10 is 1 because 10^1 = 10.'
'Log of 10000 is 4 because 10^4 = 10000.'