2 to the fourth is 16, and 6 to the second is 36. However, since it's a negative exponent, you'd have to move it down to to the bottom of the fraction, creating 1/16+36, which makes 1/52.
A child's toy consists of a piece of plastic attached to a spring in the figure below. The spring is compressed against the floor a distance of 2.00 cm, and the toy is released. If the toy has a mass of 117 g and rises to a maximum height of 45.0 cm, estimate the force constant of the spring.