* Know the conversion: 1 kilometer (km) = 1000 meters (m) and 1 meter (m) = 10 decimeters (dm)

* Combine the conversions: 1 km = 1000 m * 10 dm/m = 10,000 dm

* Calculate: 0.23 km * 10,000 dm/km = 2300 dm

Therefore, there are 2300 decimeters in 0.23 kilometers.