Question

How do you convert `2.1 x 10^-1` into expanded notation?

Answer 1

`2.1xx10^(-1) = 0.21`

Explanation:

Multiplying by `10` to a negative exponent cases the decimal point to move the absolute value of the exponent number of decimal positions to the left.

(I am assuming that by "expanded notation" you mean the same thing as what is more often referred to here as "standard notation").