I didn't got the use (**)

Answer 1

exponentiation
2**2=4
4**2=16
5**3=5*5*5=125
2**4=2*2*2*2=16

Answer 2

** means power or exponential
a**2 or a to the power 2 or a square
a**3 or a to the power three or a cube etc

2**2 = 2*2=4
2**3=2*2*2=8
3**4=3*3*3*3=81

Answer 3

Thanks ☺️