Useful properties:
PROPERTY #1: If we multiply N be 10^k (where k is POSITIVE), then we move N's decimal point k spaces to the RIGHT.
For example, 88.123456 x 10^4 = 881234.56

PROPERTY #2: If we multiply N be 10^k (where k is NEGATIVE), then we move N's decimal point k spaces to the LEFT.
For example, 1234.5678 x 10^(-3) = 1.2345678

Applying the 2nd property, we get: $12.12 × 10^{–3}=0000012.12 × 10^{–3}=0.01212$
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Now evaluate the answer choices....
A. $–1.21 × 10^3=-1210$. Does NOT equal $0.01212$.

B. $0.012$. Does NOT equal $0.01212$.

C. $0.00001212 × 10^3=0.01212$. YES this IS equal to $0.01212$.

D. $0.01212 × 10^3$=12.12[/quote]. Does NOT equal $0.01212$.

Answer: C

Cheers,
Brent