Okay I don't want to be rude, but that's a pretty...well how can I put it? It's just a question most people would know the answer to off the top of their head. But it's not for me to judge you so here we go: The answer is...(drumroll)...4mm! By the way I am assuming you mean 4 millimetres and 8 millimetres.
4mm is smaller than 5mm
An object measuring 8mm by 4mm is relatively small, approximately the size of a small button or a piece of candy. To visualize it, 8mm is just over 0.3 inches, while 4mm is about 0.16 inches. This size makes it suitable for applications requiring compact dimensions, such as electronics or jewelry components.
1.8 mm is smaller than 8mm. 8mm is 4.44 times 1.8.
Smaller 3cm = 30mm so 8mm is 22mm smaller than 30mm or 3cm
The urethra is bigger. Ureters average 3-4mm in diameter, while urethras average 6-8mm.
A 4mm diamond measures 4mm in at least one measurement.
Mount Everest is not getting smaller. Every year the mountain grows about 4mm as a result of the upward thrust generated by two opposing tectonic plates.
As wide as 4mm on a ruler
4mm its in the question
4mm is 0.15748032 of an inch.
4mm-6mm in inches = -2
Not sure what your working on but it might be 3/8" and not metric.