Introduction to Multiplication and Division

EMA1501 - Emergent Mathematics · Numbers and Operations

Introduction to Multiplication and Division

Multiplication and division are two of the four basic operations in mathematics. They are essential for understanding more complex mathematical concepts. In this section, you will learn the principles of multiplication and division, how they relate to each other, and how to apply them in practical situations.

Understanding Multiplication

Multiplication can be thought of as repeated addition. For example, if you want to multiply 3 by 4 (written as 3 × 4), it means you add 3 together four times:

3 × 4 = 3 + 3 + 3 + 3 = 12

In this case, 3 is called the multiplicand, and 4 is the multiplier. The result, 12, is known as the product.

Multiplication Facts

It is helpful to memorise multiplication facts, often referred to as times tables. Here are some basic multiplication facts:

  • 1 × n = n (for any number n)
  • 2 × n = n + n
  • 3 × n = n + n + n
  • 4 × n = n + n + n + n

For example, 2 × 5 = 10, which is the same as adding 5 two times (5 + 5 = 10).

Watch out:

Watch out: Be careful not to confuse multiplication with addition. Remember that multiplication is repeated addition.

Using Arrays to Visualise Multiplication

Arrays are a useful way to visualise multiplication. An array is a set of objects arranged in rows and columns. For example, to represent 3 × 4 using an array, you can draw three rows with four objects in each row:

• • • •
• • • •
• • • •

This array shows that 3 rows of 4 objects each make a total of 12 objects.

Understanding Division

Division is the process of splitting a number into equal parts. It can be thought of as the opposite of multiplication. For example, if you divide 12 by 4 (written as 12 ÷ 4), you want to find out how many groups of 4 can be made from 12:

12 ÷ 4 = 3

In this case, 12 is the dividend, 4 is the divisor, and 3 is the quotient.

Division Facts

Just like multiplication, it is helpful to memorise division facts. Here are some basic division facts:

  • n ÷ 1 = n (for any number n)
  • n ÷ n = 1 (for any number n, except 0)
  • 10 ÷ 2 = 5
  • 15 ÷ 3 = 5

For example, 20 ÷ 5 = 4 means that if you have 20 objects and you divide them into groups of 5, you will have 4 groups.

Watch out:

Watch out: Division by zero is undefined. You cannot divide any number by zero.

Multiplication and Division Relationship

Multiplication and division are closely related. If you know a multiplication fact, you can easily find the corresponding division fact. For example, if you know that:

3 × 4 = 12

Then you also know that:

12 ÷ 4 = 3

and

12 ÷ 3 = 4

Word Problems Involving Multiplication and Division

Word problems can help you apply multiplication and division in real-life situations. Here are some examples:

Example 1: Multiplication Word Problem

A farmer has 5 fields. Each field has 6 rows of corn. How many rows of corn does the farmer have in total?

To solve this, use multiplication:

5 × 6 = 30

The farmer has 30 rows of corn.

Example 2: Division Word Problem

A baker has 24 cupcakes. He wants to pack them into boxes with 6 cupcakes each. How many boxes does he need?

To solve this, use division:

24 ÷ 6 = 4

The baker needs 4 boxes.

Using Multiplication and Division in the Classroom

When teaching multiplication and division to young learners, use engaging methods. Here are some strategies:

  • Use physical objects, such as blocks or counters, to demonstrate concepts.
  • Incorporate games that involve multiplication and division.
  • Encourage students to create their own word problems.
  • Use visual aids, such as arrays or number lines, to help students understand.

Summary

  • Multiplication is repeated addition, and division is splitting into equal parts.
  • The product is the result of multiplication, while the quotient is the result of division.
  • Multiplication and division are related; knowing one helps you understand the other.
  • Word problems help apply multiplication and division in real-life situations.

Check your understanding

  1. What is the product of 7 and 8?
  2. If you have 36 apples and want to divide them into bags of 9, how many bags do you need?
  3. Explain how multiplication can be seen as repeated addition.
  4. What happens if you try to divide a number by zero?