668 kilograms is equal to blank tonne.
It is true that one ton is equal to 1000 kilograms, so we could set up a proportion to solve. So we know that 668 kilograms is equal to 𝑥 number of tonnes, and we know that 1000 kilograms is equal to one ton. So we can cross multiply and solve for 𝑥 number of tonnes.
And when we cross multiply, we can simply use the numbers and know that our answer will be in tonnes. So we have one times 668, which is 668, and then we multiply 1000 times 𝑥.
So to solve for 𝑥 we need to divide both sides of the equation by 1000. The 1000s cancel on the right, and 668 divided by 1000 is equal to 0.668. So this means that 668 kilograms is equal to 0.668 tonne.