Rules for Signs in Algebra

Algebra is a part of mathematics deals with operations and rules of arithmetic of symbols and numbers, usually letters of the alphabet to express general relationships that hold for all members of the set. Rules for signs in algebra tell us what we are allowed to write. Operations are addition, subtraction, multiplication and division in algebra.

I like to share this Sig Fig Rules with you all through my article. 

Addition rules for signs in algebra:

If the expressions signs are the same, we can add and keep the sign. Otherwise expressions signs are different we can do subtract the expression and take the sign attached to the larger number value.  
Example
- 5 + - 8 = - 13

Subtraction:
Add the Opposite:

1. Change the subtraction sing into addition.
2. Change the sign of the second term to its opposite.

Example:
5 - (+ 2) = 3 {Since 2 is positive.}
5 + (- 2) =3  {Add the opposite.}
4 + (+ 2)= 6 {we can exchange - ( - ) with + +}.
           The subtraction rules for signs in algebra means that the operations of sequences - ⁺ and + ^- are interchanged.

Multiplication and division rules for signs in algebra:

If the expressions signs are the same, the result is opposite; otherwise negative.

Table for multiplication rules for signs in algebra:

+  x  +	=	+
-  x -	=	+
+  x  -	=	-
-x +	=	-

Table for division rules for signs in algebra:

+÷+	=	+
-÷-	=	+
+÷-	=	-
-÷+	=	-

Practice problems regarding rules for signs in algebra:

Problem 1:  -7 + -13
Solution:
   = -7 + (-13)
Add the two terms
   = -20 (answer)

Problem 2:  -`7/8` - -`5/8`
Solution:
   ⁼ - `7/8` + `5/8`
Change second term sign
    ⁼ - `7/8` + `5/8`
   = -`2/8`
   = - `1/4`

Problem 3:  -1 - 5
Solution:
=-1 - 5
Add the terms
=-6

Problem 4:  49 +( -15)
Solution:
=49 + -15
Subtract the terms
=34

Problem 5:
`1/2` - `1/8`
Solution:
=`1/2` - `1/8`
Subtract the terms:
  = `3/8`

Problem 6: 
`3/8` ÷ `1/8`
Solution:
= `3/8` ÷ `1/8`
Change the sing and second term
=`3/8` * `8/1`
= 3

Problem 7: -(-5)
Solution:
=+5

Problem 8: -2 + -2 + -2 + -2
Solution:
Add the all terms
=-8

Problem 9: 13 ÷-2
Solution:
=-7.5


My forthcoming post is on sample papers for class 12 cbse and sample papers for class 9 will give you more understanding about Algebra.

Problem 10:  -`3/8` (16)
Solution:
Multiply the terms
= -`48/8`
=-6

Problem 11: 3 + 3 + 3 + 3
Solution:
Add all term
=12

Problem 12:  -6(-3)
Solution:
=+18