# Understanding Multiplication

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Category: Education

## Presentation Description

Reteaching multiplication with images.

## Presentation Transcript

### Today We Are Learning How To Multiply :

Today We Are Learning How To Multiply

### Understanding Multiplication :

Understanding Multiplication When the same numbers are added over and over again, a simpler way of reaching the same result is to use multiplication.

### Understanding Multiplication :

Understanding Multiplication Example: If you know there are 5 pennies in every nickel and you have 7 nickels, how would you figure out how many pennies are in 7 nickels? You could add 5, seven times: 5+5+5+5+5+5+5= 35 or You could simply multiply 5 X 7 = 35

### Understanding Multiplication :

Understanding Multiplication Read the multiplication word problem below. Each house has four people living in it. How many people live in the houses? 3 × 4 = 12 people 4 + 4 + 4 = 12

### Understanding Multiplication :

Understanding Multiplication There are 7 rocks in each box. That is a total of how many rocks? 7 + 7 + 7 + 7 = 28 4X7 = 28

### Understanding Multiplication :

Understanding Multiplication The easiest way to find the total number of items in equal groups is to use multiplication. Multiplication allows you to do repeated addition quickly and efficiently.

### Multiplication Using Grouping :

Multiplication Using Grouping Another way to look at it would be equal grouping. We are going to use 3X4 as our example. Example: 3X4=12 Lets interpret 3X4 as 3 groups of 4.

### Multiplication Using Grouping :

Multiplication Using Grouping Lets find 3X4 by counting the dots one by one. 4 + 4 + 4 = 12 You see 3 groups of 4. Therefore 3X4 = 4 + 4 + 4 Multiplication can be solved by repeated addition.

### Multiplication Using Skip Counting :

Multiplication Using Skip Counting We could also skip count by 4. 4 8 12

### Multiplication Using Arrays :

Multiplication Using Arrays Lets use another approach to understanding multiplication. We will now use an array. You are going to be able to represent 3X4 not as 3 separate groups, but as 3 rows of 4 objects as shown below.

### Multiplication Using Arrays :

Multiplication Using Arrays Can you see 3 groups of 4 in the array. Each row represents 3 groups of 4. Now can you see 4 groups of 3. Each column represents 4 groups of 3.

### Multiplication Using Arrays and Skip Counting :

Multiplication Using Arrays and Skip Counting Lets use the array below to use the strategy of skip counting. The array below shows 4X8 drawn as an array of 4 rows of 8 dots. 4 8 12 16 20 24 28 32

### Understanding Multiplication :

Understanding Multiplication Now that we have reviewed several ways for understanding multiplication lets review the multiplication table on the next slide.

### Multiplication Table :

Multiplication Table Look at the multiplication table below.

### Multiplication Table :

Multiplication Table Use the multiplication table to find the product of 3 and 9, locate 3 in the first column and then find 9 in the top row. Follow the 3 row to where it meets the 9 column. The number in the square where the column and row meet is the product

### Multiplication Table :

Multiplication Table See the shaded area in the table below. 3X9=27

### Understanding Multiplication :

Understanding Multiplication When multiplying numbers it is important you know the following terms: 1. Factors 2. Products Factors – are the numbers being multiplied. Products – are the result of multiplication (simply put the answer).

### Understanding Multiplication :

Understanding Multiplication There are three different ways you can write a multiplication sign: 1. You can use the multiplication (times) sign: 2 X 4 = 8 2. A dot between the numbers: 2 ∙ 4 = 8 3. Parentheses: (2) (4) = 8

### Understanding Multiplication :

Understanding Multiplication Multiplication can also be shown: Horizontally → 9 X 6 = 54 or Vertically ↓ 9 X 6 54 When it is shown vertically, the bar under the second factor represents the equal sign.

### Understanding Multiplication :

Understanding Multiplication The zero multiplication facts: Any number times zero is always zero. Multiplication is repeated addition so: 0 X 3 = 0 → 0 + 0 + 0 = 0 It does not matter which number is first when you write the problem. The answer is the same. This is called commutative property of multiplication. 3 X 0 = 0 or 0 X 3 = 0 ( The numbers can be switched around and the answer is still the same. This is true for all multiplication problems.)

### Understanding Multiplication :

Understanding Multiplication The 1’s multiplication facts: Any number times 1 is always itself. Multiplication is repeated addition so: 1 X 4 = 4 → 1 + 1 + 1 + 1 = 4 Because of the commutative property of multiplication: 1 X 4 = 4 or 4 X 1 = 4

### Understanding Multiplication :

Understanding Multiplication The 2’s multiplication facts: Any number times 2 is that number doubled. Multiplication is repeated addition so: 2 X 4 = 8 → 4 + 4 = 8 Because of the commutative property of multiplication: 2 X 4 = 8 or 4 X 2 = 8

### Understanding Multiplication :

Understanding Multiplication This concludes Part 1 on learning how to multiply.

### Multiplication :

Multiplication THE END