So, you're dealing with a unit conversion that must get you from "cL"cL, or centiliters, to "nL"nL, or nanoliters.
One centiliter is equal to 10^(-2)"L"10−2L, and one nanoliter is equal to 10^(-9)"L"10−9L, so you're going from something small to something even smaller. This means that the result must be a bigger number than 35.7, since there are more nanoliters in a liter than there are centiliters in a liter.
You can do this by going to liters first
"35.7 cL" * ("1 L")/(10^2 "cL") * (10^9"nL")/("1 L") = 35.7 * 10^(7)"nL"35.7 cL⋅1 L102cL⋅109nL1 L=35.7⋅107nL
or by going directly from centiliters to nanoliters
"35.7 cL" * ("1 nL")/(10^(-7)"cL") = 35.7 * 10^(7)"nL"35.7 cL⋅1 nL10−7cL=35.7⋅107nL
Because 1 liter has 10^2102 centiliters and 10^9109 nanoliters, one centiliter will have
"1 cL" * ("1 nL")/(10^(-7)"cL") = 10^7"nL"1 cL⋅1 nL10−7cL=107nL
Unit conversions like this one will become a walk in the park once you'll get comfortable with the SI metric prefixes
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