(23 km/L) · (3.785 L/gallon) · (1 mile/1.609344 km) =
(23 · 3.785 · 1 / 1.609) · (km · Liter · mile) / (Liter · gallon · km) =
54.1 mile/gallon .
The Canadian's car is more fuel efficient than your car is.
This should not surprise you. The average cost of gasoline in Canada right now (October 2018) is a little over USD3.80 a gallon, compared to $2.60 in the US.