If Aya's mass is 37 kg, what is her mass on the moon in kg?

The mass is not changing from place to place in the
universe. Mass is  relating to the content of matter of a rigid body. What changes from
place to place is the weight of an object which is due to the property of the
gravitational attraction  between any two bodies in the universe. The gravitational
attraction depends on the mass of two bodies and the  distance between the centre of
masses of the bodies.

The gravitational attraction on a
planet is thus the main force between an object considering  prediminant huge mass of
the planet compared to any other surrounding relatively smaller
objects.

g = 9.81 m/s^2 is gravitational acceleration on
the surface of earth approximately .

g' = 1.62m/s on the
surface of the moon.

Weight force = m*gravitational
acceleration.

So on earth Aya weighs = Aya' mass*g =
37*9.81N. So Aya has the force of weight  of 362.97 Newton on
earth.

On moon she weighs 37*1.62 N= 59.94N.Therefore Aya
weighs 5.94 N on moon which is roughly 1/6 th of the weight on
earth.