Answer
6 dam
Work Step by Step
We need to move the decimal point three places to the left. Therefore, we need to use a unit that is equal to 1000 cm and this unit is $dam$ (decameter). We know that 1 dam = 1000 cm. We can convert 6000 cm to units of dam.
$6000~cm = \frac{6000~cm}{1}\times \frac{1~dam}{1000~cm} = 6~dam$
