Scientific notation can be scary but it really is simple
the exponent after the 10 is how many places you move the decimal. If it is positive you move it right, if it negative you move it left
2 x 10^2 means you move the decimal place right twice to make 200
4 x 10^-3 means you move the decimal place left three times to make .004
The question is asking you to multiply 900000 and .0000006