Significant Figures Math Example 1

Solution

1. 1
   (a) $0.00420$: leading zeros are not significant. The digits $4$, $2$, $0$ are significant (trailing zero after a non-zero digit past the decimal point counts). $3$ significant figures.
2. 2
   (b) $3{,}050$: without a decimal point, the trailing zero is ambiguous. The definite significant figures are $3$, $0$ (the middle zero between non-zeros counts), $5$ — at least $3$ sig figs; the trailing zero may or may not be significant.
3. 3
   (c) $7.300 \times 10^4$: scientific notation makes it clear. Digits $7$, $3$, $0$, $0$ are all significant. $4$ significant figures.