How many moles of sulfur dioxide are in 2.26x10^33 sulfur dioxide molecules? ( show all work, i'm homeschooled and i'm very confused)

The formula for finding how many moles of a substance when given the amount of molecules is: moles = number of molecules / Avogadro's number

moles = no. of molecules / Avogadro's number
           = 2.26 x 10^33 / 6.022 x 10^23
           = 3752906011

Round to significant figures which is 3 = 3.75 x 10^9 mol

What are the choices?