Six point two four times [or "by" or "multiplied by"] ten to the 18 [or "to the power of 18" or "to the 18th power" or "to the 18th"]. Note that 'to the power of 2" is 'squared', and "to the power of 3" is 'cubed'.

Athletics commentators are tending more and more to say "point twenty four", but this is mathematically confusing (at least, it is over here - where we have maths rather than math .)

In algebra, when there is an expression in brackets, it's common to sayintorather thanby:a(a+b) is "a intoaplusb".

b