An astronomer measures the distance from Earth to a newly-discovered asteroid. The distance is

3.513 x 10^10m. What is the distance in gigameters? answer as a decimal.

I understand the formula as:

3.513/1 m X 1Gm/10^9 m

My confusion comes in at this first step and I don't know where to proceed.

When I look at other problems and solutions, it's not explained how they are multiplied. I am very literal and need step-by-step explained in detail.