A force that is applied to a seesaw along a line that does not extend through the axis of rotation (i.e., the fulcrum) will cause the seesaw to rotate. The direction of rotation depends on the direction of the force. And the sign on the resulting torque is associated with the direction of rotation of the seesaw.
 

When a force is applied to a seesaw in a direction that does not extend through the axis of rotation (i.e., the fulcrum), a torque is said to exist. A torque in and of itself will cause a seesaw to rotate about its fulcrum. The direction that it rotates can be described as counter-clockwise or clockwise. This direction of rotation can be determined by the direction of the force and the side of the fulcrum upon which it is exerted. In the event that it is not obvious, an upward force applied on the right side of the fulcrum or a downward force applied to the left side of the fulcrum will cause a counter-clockwise rotation. On the other hand, a downward force applied on the right side of the fulcrum or an upward force applied to the left side of the fulcrum will cause a clockwise rotation.

A torque is typically assigned a positive or a negative sign based on the direction of rotation that it causes. A torque that causes a counter-clockwise rotation is a positive torque. On the other hand, a torque that causes a clockwise rotation is a negative torque.