Service manual

STP 11-25R13-SM-TG
Q - 15
(4) When subtracting larger binary numbers, complete the borrowing process before subtracting to
reduce any chance of error. For example, to subtract 101
2
from 1000
2
requires borrowing a 1 from the
next-higher-order filled column. Looking at the problem, 1000
-101
, the only filled column is the one on the far
left. Borrowing this 1 changes it to a 0 and produces two ones in the next-lower-order column as shown:
1
01
1000
-101
(5) Now there is a 1 that can be borrowed for the next-lower-order column as shown:
11
011
-101
(6) Repeating this process produces the following results, and subtraction can be accomplished.
111
0111
1000
-101
(7) The next example uses all of the rules of binary subtraction and is checked using binary
addition.
11 1 Check:
01101
101100
10010110 +01101010
-101100 10010110
10010110
2
= 150
10
(8) Converting the binary number to a decimal number and performing the following subtraction
can also solve the preceding problem.
- 101100
2
= 44
10
01101010
2
= 106
10
(9) Subtract the following binary numbers. The subscripts are understood to be 2.
(a) 1001 (b) 10010010 (c) 11101000 (d) 111010
-1000
-1101010 -101011 -101110
(e) 110010010 (f) 1010 (g) 10110 (h) 1001011
-1110101 -1001 -10010 -111101
(i) 100001 (j) 1001100
-11111
-11101
f. The Octal System
(Conversion). It should be very clear by now that binary numbers can be
lengthy. The octal number system is used to reduce large binary numbers to smaller octal numbers.
(1) There are many ways to display the binary readout (indication) from a computer. Some
readouts are displayed on an oscilloscope, a printer, or directly in decimal using a digital voltmeter. Many