Paulina works out with a 2.5 kilogram mass. what is the mass if the 2. kilogram mass in grams

The question is basically asking us to substitute 2.5 kgs for grams, and the answer is 2500 grams. "kilo" means thousand so a Kilogram is a thousand grams. 2 kilograms are 2000 grams and 2.5 kilograms are 2500 grams. When you are asked to express a kilogram mass in grams, all you need to do is to multiply it by a 1000.

Kilograms and grams are units used to measure masses.
1000 grams are equivalent to 1 kg.
kilograms are used when there are larger masses, for simplicity and ease to make the numbers smaller we convert grams to kilograms
since 1 kg equals - 1000 g
then 2.5 kg equals - 1000 g/kg x 2.5 kg = 2500 g
the mass in grams is 2500 g