Express 450. nm in m

Question

My professor got the answer 4.50 X 10^-7 ow did he get to this please explain all steps and  he moved the decimal point over he doesn't let us use a calculator so all steps are important 

Answer 1

1 nm = 10^-9 m

 

450 nm = 450 x 10^-9 m

 

450 x 10^-9 = 4.50 x 10^-7 (move the decimal 2 places to the left, and raise the exponent by 2)

 

450 nm = 4.50 x 10^-7 m