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Carry and Borrow Principles | Up
Neets Module 13-Introduction to Number Systems and Logic Circuits | Next
THE BINARY NUMBER SYSTEM |
1-8
Table 1-1. —Decimal Addition Table
To add 5 and 7 using the table, first locate one number in the X row and the other in the Y column.
The point in field Z where the row and column intersect is the sum. In this case the sum is 12.
SUBTRACTION.¾The following definitions identify the basic terms you will need to know to
understand subtraction operations:
· SUBTRACT¾To take away, as a part from the whole or one number from another
· MINUEND¾The number from which another number is to be subtracted
· SUBTRAHEND¾The quantity to be subtracted
· REMAINDER, or DIFFERENCE¾That which is left after subtraction
· BORROW¾To transfer a digit (equal to the base number) from the next higher order column
for the purpose of subtraction.
Use the rules of subtraction and subtract 8 from 25. The form of this problem is probably familiar to
you:
It requires the use of the borrow; that is, you cannot subtract 8 from 5 and have a positive difference.
You must borrow a 1, which is really one group of 10. Then, one group of 10 plus five groups of 1 equal
15, and 15 minus 8 leaves a difference of 7. The 2 was reduced by 1 by the borrow; and since nothing is
to be subtracted from it, it is brought down to the difference.
Since the process of subtraction is the opposite of addition, the addition table 1-1 may be used to
illustrate subtraction facts for any number system we may discuss.
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