Problem: The number of digits in the number N=212×58N=2^{12} \times 5^{8}N=212×58 is
Answer Choices:
A. 999
B. 101010
C. 111111
D. 121212
E. 202020 Solution:
Rearranging the factors, N=24(28×58)=16×108=1,600,000,000\mathrm{N}=2^{4}\left(2^{8} \times 5^{8}\right)=16 \times 10^{8}=1,600,000,000N=24(28×58)=16×108=1,600,000,000 which is a ten digit number.