For us Americans to really get used to metric units, we shouldn't keep doing precise conversions except when they're necessary. Just use them. Get used to them the same way we got used to our customary units. Immersion. Occasional conversions, like guided immersion for languages, can help, but don't try to make them any more precise than needed. We've all seen rulers with inches on one edge and centimeters on the other, so we all know that a foot is 30 cm, or close enough. 30.5 if you like, but usually not needed. 30.48 exactly, but it doesn't matter 99% of the time. So if I'd done the exact conversion I'd have rounded it to 61 cm, but since pilots' heights vary by more than a cm, the quick and dirty 30 cm to the foot is all that's needed. Then just start thinking of babies as about 60 cm, a big baby as about 70 cm, etc., and stop doing conversions. (Now I want to see a baby piloting a tie fighter.)
(A US nickel weighs 5 grams, which I find to be a nice familiar reference object for small masses.)
Yes. Like the ruler, use whatever is familiar to you do do those rough conversions that help you get used to metric units.So to figure out what that is without an Internet conversion page I remembered that a 4" tube is 98-101mm.
[BT-101]
60Cm is 600mm so take 4" times 6 = 2 feet.
(A US nickel weighs 5 grams, which I find to be a nice familiar reference object for small masses.)