Use manipulate to create a slider showing its current value?

i have been using manipulate to create myself a slider, but i have my result at certain point when i move the slider, but i am not able to find the value at which my slider is at currently, kindly reply

The simplest way is to click on the “+” icon to the immediate right of the slider.

A slider in a Manipulate will display its current value, expliticly, if it has the option Appearance → “Labeled”

Manipulate[
 	moment = w*fos*l^2*0.125,
 	{w, 1, 500, 10, Appearance -> "Labeled"},
 	{fos, 1.5},
 	{l, 1, 16, 1, Appearance -> "Labeled"},
 	FrameLabel -> "moment"
 ]