A girl stood on a scale. She weighed 58 kilograms. Her and her cat weighed 61 kilograms. How much does her cat weigh?
We could use a bar model to help us think about this question. We know that the girl and her cat weighed 61 kilograms. We also know that the girl weighed 58 kilograms. We need to work out how much the cat weighs. To do this, we can find the difference between 61 kilograms and 58 kilograms. Or if we take away the girl’s mass from the total mass, that will tell us the mass of the cat.
So, we need to find the difference between 58 and 61. To find the difference between 58 and 61, we can start counting at 58 and count forward until we reach 61, one, two, three. The difference between 58 and 61 is three kilograms. So, the cat weighs three kilograms.