Yes, 2.51 x 10-3 does indeed equal 0.00251.
-125
-729
-216
-4-3 = -1/64
6.9110 to the negative 3rd power (6.911-3) equals 0.0030295444 (rounded).
0.001
1/216
That's the same as 1 divided by (x to the power 3).
1/8 or .125
It is n cubed.
10-3 = 1/103 = 0.001
a, a^3*a^-2 is a^3+-2 which equals just a