3.14 x 10⁻³ has the value 0.00314
The exponent tells us the number of times the decimal has to move. The sign of the exponent tells us the direction of the movement of the decimal.
The negative sign of the exponent means that the decimal has to move to the right.
From 0.00314, decimal move to the right 0003.14
If the decimal is positive, it means that the decimal point moved to the left of the number.
3.14 x 10³ in expanded form is 3140
From 3140. decimal move to the left 3.140