Example:
15 Gm/L = 6.819149e+10 meter per UK gallon
1 Gm/L = 4.546099e+9 meter per UK gallon | 1 meter per UK gallon = 2.199688e-10 Gm/L
Conversion Steps:
15 × (1e+9 / 0.219968799) = 6.819149e+10