Conversion

Easiest way to convert small binary numbers to decimal number is summing up the high bits(1) with: 2^(position of the bit) . Remember position counting starts with 0 and from right hand side. Now, for this question: high bits occurs at 2nd, 5th, 6th position from the right.

So the decimal number will be: $2^2+2^5+2^6 = 100$

using rule 64 32 16 8 4 2 1 values are 1 1 0 0 1 0 0 64+32+4=100