**Problem:**

How many kilograms are in 250 marbles if each marble is 5 grams?

**Solution:**

First, determine the total mass of the marbles.

mass of all marbles = number of marbles x mass of each marble

mass of all marbles = 250 marbles x 5 g/marble

mass of all marbles = 1250 grams

Second, convert grams to kilograms.

There are 1000 grams in 1 kilogram.

Set up the conversion so the desired unit will be cancelled out. In this case, we want kg to be the remaining unit.

mass of all marbles in kg = (mass of all marbles in g) x (1 kg/1000 g)

Note how the grams unit will be cancelled out in this equation.

mass of all marbles in kg = (1250)/1000

mass of all marbles in kg = 1.250 kg

**Answer:**

There are 1.250 kg in 250 marbles.