1, 8 km + 2,6 dam = ……….dm

1,8 km = 18.000 dm
2,6 dam = 260 dm
Total = 18.260 dm

1,8 km = 18000 dm
2,6 dam = 260 dm
1,8 km + 2,6 dam = 18000 dm + 260 dm = 18260 dm