|
(1) To calculate A + B = C
- Click the top ruler and drag it until its left edge is over A on the bottom ruler (green line).
- Click on the small black bar at the top, to move the vertical indicator (hairline) until it is at B on the top ruler (red line).
- The answer C is given by the location of the hairline on the bottom ruler (blue line).
|
(2) To calculate C - B = A
Reverse the addition procedure:
- Move the hairline until it is at C on the bottom ruler (blue line).
- Move the top ruler until the hairline is over B on the top ruler (red line).
- The answer A is on the bottom ruler, as indicated by the left edge of the top ruler (green line).
|
