Is 2.5 m bigger than 25 dm?
They are equivalent.
The length of a tissue box is most likely 25 cm. 25 m, or meters, would be far to large. One meter is about the length of a yard. 25 dm, ordecimeter's would also be wrong. There are ten decimeters in one meter. Therefore, 25 decimeters would be longer than 2.5 meters, which is much longer than a tissue box.