Subtract the following hexadecimal numbers. Check using decimals. $15 - \mathrm { A } 1$
A) -A17
B) -A14
C) -87
D) -86
E) -85

Question

Quizplus · Accepted Answer

To subtract hexadecimal numbers, we need to borrow from the next place value if the value in the minuend is less than the value in the subtrahend. 
In this case, we cannot directly subtract 1 from 5 in the units place, so we borrow 1 from the 16s place and add it to the 1 in the units place, making it 11. Then we subtract 1 from 11, which gives us 10. 
The resulting difference is 4 in the units place. 
Next, we move on to the 16s place. We cannot directly subtract A from 0, so we borrow 1 from the 256s place, making it F. Then we add 16 to 0, making it 16, and subtract A from 16, which gives us 6. 
The resulting difference is 64 in the 16s place. 
Therefore, the difference is 64 + 4 = 68 in hexadecimal. 
To check using decimals, we can convert the hexadecimal numbers to decimal form and subtract them. 
15 = 1 x 16^1 + 5 x 16^0 = 21 
A1 = 10 x 16^1 + 1 x 16^0 = 161 
So, the difference is 21 - 161 = -140 
Converting 68 to decimal form gives us 104, which confirms that the answer is D.

Subtract the Following Hexadecimal Numbers 15−A115 - \mathrm { A } 115−A1

Subtract the Following Hexadecimal Numbers $15 - \mathrm { A } 1$