Convert the number to binary. Use the standard algorithm for converting a decimal number into a binary number. Find the largest power of 2 that can divide the number in question. Write a 1 in the digit position for that power of 2. For example, if it is the 3rd power of 2, write 1 in the third digit place from the left. Subtract the power of 2 from the original number. See if the next power of 2 can divide the number. If so, place a 1 in the corresponding digit space. Do this until you have subtracted your original number to 0. Alternatively you can use a decimal-binary converter. As an example, convert 12 to binary. The largest power of 2 that can divide 12 is 8; 8 is the 4th power of 2, so the first 1 digit goes in the fourth position. Subtracting 8 from 12 leaves 4. The next power of 2, 4, can divide 4, so the third digit is also 1. Subtracting 4 from 4 leaves 0. Thus, the remaining digits are all 0. Hence, in binary, write 12 as 1100.
Find the most significant bit. Recall the bit-system you are using. The most significant digit is the digit “n” digits from the left for a “n-bit” system. If you are using a 4-bit system, for example, you will find the most significant digit in the “thousands” place. For example, the number 12, which is 1100 in binary, has the most significant digit 1 in a 4-bit binary system.
Find the least significant bit. Look at the right-most digit in the binary number. This is the least significant bit. For the number 12, written in binary as 1100, the least significant digit is 0.