#### Answer

(a) $423.\underline{00}6 \space mL$, $6$ significant figures, $4.23006 \times 10^{2} \space mL$.
(b) $0.001\underline 0 73 \underline 0 4 \underline 0 \space g$, $7$ significant figures, $1.073040 \times 10^{-3} \space g$.
(c) $1,\underline{0}81.\underline{0}2 \space pounds$, 6 significant figures, $1.08102 \times 10^3 \space pounds.$

#### Work Step by Step

1. For decimal numbers, the 0s to the right of the first non-zero figure are signficant figures, counting from left to right.
2. Count the number of non-zero figures and add the number of underlined zeros.
3.
- Move the decimal point to the left of the first non-zero figure.
(a) $4.23006 $
(b) $1.073040$
(c) $1.08102$
- Add the $10^x$ part based on the places you moved.
(a) Since we moved the decimal point by two places to the left, we multiply it by $10^2$.
(b) Since we moved the decimal point by three places to the right, we multiply it by $10^{-3}$
(a) Since we moved the decimal point by three places to the left, we multiply it by $10^3$