253 has three significant figures. (Any digit that is not a trailing or leading zero is a significant figure.)
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Actually, a trainiling zero AFTER a decimal point IS an indicator of the degree of accuracy of the number and so is a sf.
there are 3 sig figs. 4, 0, and 5 are the sig figs
5 sig figs
61 has 2 sig figs.
There are five sig figs
There are four sig figs in 2.905.
There are three sig figs in 1.05.
There are three sig figs in 4890.
All five of them are sig figs
There are two sig figs in 3700000.
There are two sig figs in 290.
There are five sig figs in 4.1275.
6.002 has four sig figs.