#### Answer

a) ambiguous
b) 3 significant figures
c) 2 significant figures
d) 5 significant figures
e) 4 significant figures
f) ambiguous
g) 3 significant figures
h) ambiguous

#### Work Step by Step

a) 450
There is one terminal zero that precede the decimal point in a quantity bigger than one, so this case is ambiguous.
b) 98.6
All the digits are significant, since they are nonzero digits. So this number has 3 significant figures.
c) 0.0033
All the zeros preceding the first nonzero digit are not significant. So this number has 2 significant figures.
d) 902.10
The zeros between nonzero digits and at the end of the number to the right of the decimal point are significant. So this number has 5 significant figures.
e) 0.02173
All the zeros preceding the first nonzero digit are not significant. So this number has 4 significant figures.
f) 7000
There is three terminal zeros that precede the decimal point in a quantity bigger than one, so this case is ambiguous.
g )7.02
The zero between nonzero digits is significant. So this number has 3 significant figures.
h) 67,000,000
There is six terminal zeros that precede the decimal point in a quantity bigger than one, so this case is ambiguous.