BNU1501 - Basic operations on numbers and variables

Overview of Basic Operations

• Goals: Understand basic operations on numbers & variables, perform calculations correctly.

Basic Operations on Numbers

• Four Basic Operations: Addition, Subtraction, Multiplication, Division.

  • Addition: Sum or total.

  • Subtraction: Difference.

  • Multiplication: Product.

  • Division: Quotient.

Importance of Signs

• Same Signs:

  • Positive + Positive = Positive

  • Negative + Negative = Positive

• Different Signs:

  • Positive x Negative = Negative

  • Negative x Positive = Negative

Operations on Variables

• Like Terms: Only terms with the same variables can be added or subtracted.

• Separating Terms: Terms are separated by + or - signs.

• Coefficients: Add or subtract coefficients when simplifying like terms.

  • Example: 6a + 3a = 9a.

• Invisible Coefficient: There is an invisible one before any variable (e.g., x = 1x).

• Alphabetical Order: Variables should be arranged alphabetically in expressions (e.g., ax + by).

Multiplying and Dividing Terms

• Multiplying: Multiply coefficients first, then variables.

  • Example: 2a x 4b = 8ab.

• Dividing: Divide coefficients first, then variables.

  • Example: ( \frac{6x}{2x} = -3 ) (x cancels out).

Key Concepts

• Higher Order Variables: Terms with exponents come first in ordering (e.g., x² before x).

• Simplification: Always keep variables in alphabetical order.

Exercises and Q&A

• Practiced through exercises on basic operations with emphasis on using rules of signs and order.

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