[golol]

Doesn't writing out the trailing zeroes mean that you clain 4 significant digits? At least in the physics context.

[busyant]

I think there are a few conventions for expressing sig digits.

Where I was taught…

2600 has 2 sd

2600. Has 4 sd

2.6e3 has 2sd

2.60e3 has 3 sd

Edit. If I had been in charge of setting sd rules, I would’ve said …

2600 has 4 sd

260? Has 3 sd

26?? Has 2 sd

The fact zeros are overloaded (they can be placeholders or they can actually mean 0) is confusing to students.