Right brained children work better when they can see things in pictures. When converting from one unit of measure to another, this image will help ALL children remember, but especially right-brained children who might not remember it otherwise.
On a test, such as a state assessment, they cannot bring this in with them, but they can jot it down real quick when a conversion problem pops up. Now if you remember, there might be 2-3 of these on the whole test. Why bother to teach them this for just a couple of answers? Well, I've needed this info in real life...so it IS one of those things that is helpful to just know.