Grade can be found by measuring the horizontal length of an elevation the run and the vertical height of the elevation the rise. We calculate terrain grade in the same way we calculate the slope of a line. Thus if riserun 002 and the run is 150 the rise in feet is actually a drop.
Then you check what number of spaces you need to go up by.
The basic formula for calculating slope is rise over run. Learn how to write the slope formula from scratch and how to apply it to find the slope of a line from two points. If your equation is not in slope-intercept form you can solve for y and then the slope will be the number next to x. Slope can be calculated as a percentage which is calculated in much the same way as the gradient.