Zero in multiplication and division và

### 1.1. Knowledge to remember

Properties when multiplying or dividing 0 by a number.

### 1.2. Math forms

**Form 1: Calculate**

Perform the calculation when multiplying a number by 0 or 0 divided by a non-zero number.

**Form 2: Find the missing element**

To find a factor, we divide the product by the other factor.

– To find the divided number, we take the merchant with the divisor.

**Form 3: Compare**

– Perform calculations.

– Compare the calculated value

### 1.3. Solving Textbook Exercises page 133

**Lesson 1**

Mental arithmetic:

0 x 4 = 0 x 2 = 0 x 3 = 0 x 1 =

4 x 0 = 2 x 0 = 3 x 0 = 1 x 0 =

__Solution method__

The number 0 multiplied by any number equals 0.

Any number multiplied by 0 equals 0.

__Solution guide__

0 x 4 = 0 0 x 2 = 0 0 x 3 = 0 0 x 1 = 0

4 x 0 = 0 2 x 0 = 0 3 x 0 = 0 1 x 0 = 0

**Lesson 2**

Mental arithmetic:

0 : 4 = 0 : 2 = 0 : 3 = 0 : 1 =

__Solution method__

The number 0 divided by any number equals 0.

__Solution guide__

0 : 4 = 0 0 : 2 = 0 0 : 3 = 0 0 : 1 = 0

**lesson 3**

Number ?

… x 5 = 0 3 x … = 0

… : 5 = 0 … : 3 = 0

__Solution method__

Apply your knowledge of zero in multiplication and division to find the missing factor or divisor.

__Solution guide__

0 x 5 = 0 3 x 0 = 0

0 : 5 = 0 0 : 3 = 0

**Lesson 4**

Calculate:

2 : 2 x 0 = 0 : 3 x 3 =

5 : 5 x 0 = 0 : 4 x 1 =

__Solution method__

Perform calculations from left to right.

__Solution guide__

2 : 2 x 0 = 1 x 0 = 0 0 : 3 x 3 = 0 x 3 = 0

5 : 5 x 0 = 1 x 0 = 0 0 : 4 x 1 = 0 x 1 = 0

### 1.4. Solving Textbook Exercises page 134

**Lesson 1**

a) Make a multiplication table of 1: b) Make a table of division 1:

1 x 1 = 1 : 1 =

1 x 2 = 2 : 1 =

1 x 3 = 3 : 1 =

1 x 4 = 4 : 1 =

1 x 5 = 5 : 1 =

1 x 6 = 6 : 1 =

1 x 7 = 7 : 1 =

1 x 8 = 8 : 1 =

1 x 9 = 9 : 1 =

1 x 10 = 10 : 1 =

__Solution method__

– The number 1 multiplied by any number equals the same number.

– Any number divided by 1 is equal to that number.

__Solution guide__

a) b)

1 x 1 = 1 1 : 1 = 1

1 x 2 = 2 2 : 1 = 2

1 x 3 = 3 3 : 1 = 3

1 x 4 = 4 4 : 1 = 4

1 x 5 = 5 5 : 1 = 5

1 x 6 = 6 6 : 1 = 6

1 x 7 = 7 7 : 1 = 7

1 x 8 = 8 8 : 1 = 8

1 x 9 = 9 9 : 1 = 9

1 x 10 = 10 10 : 1 = 10

**Lesson 2**

Mental arithmetic:

a) 0 + 3 = b) 5 + 1 = c) 4 : 1 =

3 + 0 = 1 + 5 = 0 : 2 =

0 x 3 = 1 x 5 = 0 : 1 =

3 x 0 = 5 x 1 = 1 : 1 =

__Solution method__

Perform calculations with numbers and fill in the blanks with the results.

__Solution guide__

a) 0 + 3 = 3 b) 5 + 1 = 6 c) 4 : 1 = 4

3 + 0 = 3 1 + 5 = 6 0 : 2 = 0

0 x 3 = 0 1 x 5 = 5 0 : 1 = 0

3 x 0 = 0 5 x 1 = 5 1 : 1 = 1

**lesson 3**

Which result is 0? Which result is 1?

__Solution method__

Perform the calculation in the cells and then match with the appropriate result.

__Solution guide__

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