Question 534046
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1100 with a subscript 2 indicates that the number is written in base-2.  We normally write numbers in base ten.  You should be familiar with places in base 10.

The first digit to the left of the decimal is the ones (10^0), then the next is the tens (10^1), hundreds (10^2), thousands (10^3), and it continues.  

In base-19 1100 is one thousand, one hundred.

1's - 0
10's - 0
100's - 1 = 100
1000's - 1 = 1000

1000 + 100 = 1100

In base two the the first digit to the left of the decimal is the ones (2^0), then the next is the twos (2^1), then the fours (2^2) then the 8's (2^3) and it continues.

1100 in base-2 is:

1's - 0
2's - 0
4's - 1  = 4
8's - 1 = 8

That's 8+4 = 12 in base-10 notation.