I feel your pain. As part of Europe we switched to metric, although I was taught in Imperial. All weights and measures are sold by the kilo and metre.
Luckily most quilt patterns are in inches (although we have to buy our fabric by the metre
)
2.5 cm and 25mm are the
same length - 1".
cm or centimetre is 1/10th of a metre.
mm is millimetre, a thousandth of a metre.
A metre is 39" long.
Virtually all our tape measures are two-sided. All I do is flip mine over. If you need me to send you one, pm me.