Like the poster above said, and you have to look at the context as well. 4 m by itself is 4 meters. 4 mm is 4 millimeters. m by itself usually means mass, but that's not a unit.Mudkips said:And 4M?
4m?
Meters? Million? Thousandths? Mass? etc?
SI symbols are ambiguous, no matter how many ways they try to style the character "u".
4k is interpreted as 4000 mostly due to it being common usage and k not being a unit, just a prefix. You won't see 4T being interpreted as 4 000 000 000 000 because it's not common, and T is a unit - Tesla.