Download 2-1 Adding Rational Numbers

2-1 Adding Rational Numbers
• Identity Property of Addition: For every real number n,
n + 0 = n.
– Examples:
• Inverse Property of Addition: For every real number n, there
is an additive inverse -n such that n + (-n) = 0.
– Examples:
• Rule: Adding Numbers with the Same Sign
– To add two numbers with the same sign, add the numbers
and keep the sign.
• Rule: Adding Number with Different Signs
– To add two numbers with different signs, subtract the
numbers and keep the sign of the number with the greater
absolute value.
• Ex 2: Adding Numbers
• Ex 3: Real-World Problem Solving
• Evaluating Expressions involving addition
– Substitute a value for the variable and simplify
• Note: The expression -n means the opposite of
n. It can represent a negative number, zero, or a
positive number.
• Ex 4: Evaluating Expressions
• Ex 5: Real-World Problem Solving
Matrices
• Def: A matrix is a rectangular arrangement of
numbers in rows and columns.
• Def: Each item in a matrix is an element.
 1 2
 4 0


 7 3
• To add matrices of the same size, you add the
corresponding elements.
• Ex 6: Adding Matrices