Subtraction – About subtraction – pg.1/3
Subtraction: pg. 1, 2, 3
Contents:
pg.1…..Subtraction – about subtraction
pg.2…..Subtraction – exercises
pg.3…..Subtraction – answers to exercises
About subtraction
The result of subtraction is called the difference.
Note:

When a parenthesis that is preceded by a plus sign is opened, all the terms that were inside that parentheses maintain their sign.
Example: 7x + (3a – 5 + 4b – 2c) = 7x + 3a – 5 + 4b – 2c

When a parenthesis that is preceded by a minus sign is opened, all the terms that were inside that parentheses change their sign.
Example: 5x – (4a – 3 + 2b – 5c) = 5x – 4a + 3 – 2b + 5c
There are more ways to subtract numbers.
The most common way is to subtract one number from the other.
Example:
* Subtract 3 from 7.
7 – 3 = 4
* Subtract 4 from 10.
10 – (4) = 10 +4 = 14
* Subtracting multiple numbers from one number:
Let’s assume that we need to subtract 6 and 4 and 1 and 2 from 13.
13 – [6+ (4)+1+ (2)] =13 – (6 – 4 + 1 – 2) = 13 – 1 = 12 or by opening the parentheses preceded by the minus sign, the calculation can look like: 13 – [6+ (4)+1+ (2)] =13 – (6 – 4 + 1 – 2) = 13 – 6 +4 – 1 +2 = (13 – 6) + 4 – 1 + 2 = 7 + 4 – 1 + 2 = (7 + 4) – 1 + 2 = 11 1 + 2 = (11 – 1) +2 = 10 +2 = 12
Subtraction: pg. 1, 2, 3
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