.
1-617-275-8164

Expression, Equation and Variables


Homework Help, Regular One-to-One Grade Tutoring, Email - Assignment Help

Mathematics    PreAlgebra    Expression, Equation and Variables

Expression, Equation and Variables:

Algebra is a language of symbols. We use different symbols to represent the numbers like + for
addition, - for subtraction, × for multiplication and / for division. An expression a combination of
numbers, variables and atleast one operation. An equation is a mathematical sentence which
subsumes an equal sign. In algebraic expressions, letters represent variables. These letters are
actually numbers in disguise. In this expression, the variables are x and y.

Example1:
Expression:2A+B
Equation:



Example2:
Expression: -3x+4y2z
Equation:
y = mx + c

Properties of Operations:

1. Commutative Property 
     a. Addition: The order that numbers are added does not change the sum. x + y = y + x 
     b. Multiplication: The order that numbers are multiplied does not change the product. x × y = y × x

2. Associative Property
     a. Addition: Grouping of addends does not change the sum. (x + y) + z = x + (y + z) 
     b. Multiplication: Grouping of factors does not change the products. (x × y) × z = x × (y × z)

3. Identity Property
     a. Addition: The sum of a number an zero is the number x + 0 = x
     b.Multiplication: The product of a factor and one is the factor. x × 1 = x

4. Multiplication Property of Zero
     a. Addition: The product of a number and zero is zero. x × 0 = x

5. Distributive Property: For any numbers a,b and c
     a (b + c) = ab + ac
Parts of a whole number can be written as fractions, such as 1/2, or as decimals such as 0.5, read
as "5 tenths".

Examples: 0.04 = 4/100 = 1/25
3.75 = 375/100 = 15/4
To represent a decimal on a number line, divide each segment of the number line into ten equal
parts.
Example: To represent 8.4 on a number line, divide the segment between 8 and 9 into ten equal
parts.


The arrow is four parts to the right of 8 where it points at 8.4.

Similarly, we can represent 8.456 on a number line by dividing the segment between 8.45 and 8.46 into ten equal parts.


The arrow is six parts to the right of 8.45 where it points at 8.456


Free Trial

Submit your homework or assignment.