Compare the tenths digit of all numbers:
.33
.275
.25
.3
The lower tenths digits will go on the bottom, and the higher tenths digits will go on the top:
.33
.3
.275
.25
Compare the hundredths digit of all numbers:
.33
.3
3 > 0
.275
.25
7 > 5
From thickest to thinnest, the order is .33 mm, .3 mm, .275 mm, and .25 mm.
