The expression 31⁴ in expanded format is 31 x 31 x 31 x 31.
When we raise the expression to the power of 4, it implies that 31 multiplies itself into four places.
Similarly, any number can be raised to the power of 4 and denoted as n⁴ (n raised to the fourth power).
31⁴ = 923,521
31⁴ expanded = 31 x 31 x 31 x 31
The expanded format shows the longhand manner of expressing the same expression, while 31⁴ is the shorthand way for the expression.
Thus, the correct format for the expression 31⁴ is 31 x 31 x 31 x 31.