Introduction:
In the chapter “Integers”, students are introduced to the world of positive and negative numbers, which are collectively known as integers. Integers are a crucial part of mathematics, used in various real-life situations such as temperatures, bank balances, and elevations. Understanding integers helps students grasp basic concepts of number lines, addition, subtraction, and comparisons of numbers.
Key Concepts Covered:
- What are Integers?
- Integers include all positive whole numbers, their negative counterparts, and zero.
- Example: … -3, -2, -1, 0, 1, 2, 3 …
- Integers are the set of numbers that are not fractions or decimals.
- Representation of Integers on the Number Line:
- Integers are represented on a number line where:
- Positive integers are to the right of 0.
- Negative integers are to the left of 0.
- The farther you move to the right, the larger the positive number, and the farther you move to the left, the smaller the negative number.
- Integers are represented on a number line where:
- Addition and Subtraction of Integers:
- Addition of Integers:
- Adding two positive integers gives a positive result.
- Adding two negative integers gives a negative result.
- Adding a positive and a negative integer depends on their absolute values.
- Subtraction of Integers:
- Subtracting a positive integer is like moving left on the number line.
- Subtracting a negative integer is like moving right on the number line.
- Addition of Integers:
- Multiplication and Division of Integers:
- Multiplication of Integers:
- A positive integer multiplied by a positive integer gives a positive result.
- A positive integer multiplied by a negative integer gives a negative result.
- A negative integer multiplied by a negative integer gives a positive result.
- Division of Integers:
- The same rules as multiplication apply to division.
- Multiplication of Integers:
- Properties of Integers:
- Commutative Property: Addition and multiplication of integers are commutative.
- Associative Property: Addition and multiplication of integers are associative.
- Distributive Property: Multiplication distributes over addition and subtraction.
- Order of Integers:
- Understanding how to compare integers:
- Negative integers are always less than positive integers.
- The farther a negative integer is from 0, the smaller it is.
- The farther a positive integer is from 0, the larger it is.
- Understanding how to compare integers:
Important Questions with Answers:
- What is an integer?
- Answer: An integer is any whole number, either positive, negative, or zero, that does not include fractions or decimals.
- Which is greater: -5 or -8?
- Answer: -5 is greater because it is closer to zero on the number line.
- Add: -4 + 6
- Answer: 2 (since the positive number is larger, the result is positive).
- Subtract: 3 – 7
- Answer: -4 (since we are subtracting a larger number from a smaller one).
- Multiply: -3 × 5
- Answer: -15 (a negative number multiplied by a positive number is negative).
- Divide: -12 ÷ 4
- Answer: -3 (a negative divided by a positive is negative).