Addition and Subtraction in Algebra
Algebra is an important branch of mathematics that
helps students understand patterns, relationships, and problem-solving
techniques. One of the first and most essential skills in algebra is addition
and subtraction of algebraic expressions.
In this guide, you will learn how to add and subtract
algebraic expressions step by step, with simple explanations and examples.
What Are Algebraic Expressions?
An algebraic expression is a
mathematical phrase that includes:
·
Numbers
·
Variables (such as x, y, a, b)
·
Mathematical operations (addition, subtraction, multiplication)
Examples:
·
3x + 5
·
7y − 2
·
4a + 6b − 9
Understanding Like Terms
Before adding or subtracting expressions, you must
understand like terms.
✔ Like Terms
Terms that have:
·
The same variable
·
The same power
Examples of like terms:
·
2x and 5x
·
4y² and −3y²
❌ Unlike Terms
·
3x and 3y
·
5a and 5a²
Only like terms can be added or
subtracted.
How to Add Algebraic Expressions
Example 1:
Add:
2x + 5x
Solution:
(2 + 5)x = 7x
Example 2:
Add:
3a + 4b + 2a − b
Step 1:
Group like terms
(3a + 2a) + (4b − b)
Step 2:
Add coefficients
5a + 3b
How to Subtract Algebraic Expressions
When subtracting, always change the sign
of the expression being subtracted.
Example:
Subtract:
(5x + 3) − (2x − 4)
Step 1:
Change signs
5x + 3 − 2x + 4
Step 2:
Combine like terms
(5x − 2x) + (3 + 4)
Answer:
3x + 7
Common Mistakes to Avoid
Adding unlike
terms
Forgetting to change signs during
subtraction
Ignoring brackets
Mixing variables incorrectly
✔ Always double-check your work.
Why This Topic Is Important
·
Builds the foundation for advanced algebra
·
Helps in equations and problem solving
·
Essential for exams and competitive tests
Final Thoughts
Addition and subtraction in algebra become easy when
you clearly understand like terms and sign rules.
Practice regularly, and algebra will feel simple and logical.
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Related
Algebra Topic
If
you want to understand the building blocks of algebra before practicing
addition and subtraction, read our detailed guide on
Algebraic Expressions and Terms Explained Simply
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