Math 2 Lesson: Addition Table

### 1.1. Knowledge to remember

I review how to perform addition 9, 8, 7, 6 with some of the lessons learned.

### 1.2. Math forms

**Form 1: Mental calculation**

– Need to re-apply the way of adding 9; 8; 7; 6 with a number.

**Form 2: Set and then calculate**

– Set alignment

– Perform additions from right to left.

**Form 3: Math quizzes.**

– Read and analyze the topic.

– Find a solution to the problem: Pay attention to the keyword “more”; “less than”; all”; “remaining” to use reasonable calculation

– Presenting the solution

**Form 4: Geometry**

I count triangles or quadrilaterals depending on the requirements of the problem.

- Step 1: Count the single shapes
- Step 2: Match single pictures and count the newly assembled pictures.
- Step 3: Find the total number of the two types just counted.

### 1.3. Textbook Exercises Page 38

**Lesson 1**

Mental arithmetic:

b) 2 + 9 = 3 + 8 = 4 + 7 =

5 + 6 = 3 + 9 = 4 + 8 =

5 + 7 = 4 + 9 = 5 + 8 =

5 + 9 =

__Solution method__

Do the addition and then fill in the blanks with the result.

__Solution guide__

a) 9 + 2 = 11 8 + 3 = 11 7 + 4 = 11 6 + 5 = 11

9 + 3 = 12 8 + 4 = 12 7 + 4 = 11 6 + 6 = 12

9 + 4 = 13 8 + 5 = 13 7 + 6 = 13

9 + 5 = 14 8 + 6 = 14 7 + 7 = 14

9 + 6 = 15 8 + 7 = 15

9 + 7 = 16 8 + 8 = 16

9 + 8 = 17

9 + 9 = 18

b) 2 + 9 = 11 3 + 8 = 11 4 + 7 = 11

5 + 6 = 11 3 + 9 = 12 4 + 8 = 12

5 + 7 = 12 4 + 9 = 13 5 + 8 = 13

5 + 9 = 14

**Lesson 2**

Calculate:

__Solution method__

Add the numbers from right to left and then fill in the blanks with the result.

__Solution guide__

**lesson 3**

Hoa weighs 28kg, Mai weighs 3kg more than Hoa. How many kilograms does Mai weigh?

__Solution method__

To find how many kilograms Mai weighs, we take Hoa’s weight plus 3kg.

__Solution guide__

Mai’s weight in kilograms is:

28 + 3 = 31 (kg)

Answer: 31 kg.

**Lesson 4**

In the figure below:

a) How many triangles are there?

b) How many quadrilaterals are there?

__Solution method__

– Count single shapes.

– Match two or three single shapes in turn to form other shapes and then continue counting until the end.

__Solution guide__

Enter the number in the picture:

a) There are 3 triangles: h1; h2; h3.

b) There are 3 quadrilaterals: h(1,2); h(2,3); h(1,2,3).

### 1.4. Textbook Exercises Page 39

**Lesson 1**

Mental arithmetic:

a) 9 + 6 = 7 + 8 = 6 + 5 =

3 + 9 = 6 + 9 = 8 + 7 =

5 + 6 = 9 + 3 =

b) 3 + 8 = 4 + 8 = 2 + 9 =

6 + 7 = 5 + 8 = 4 + 7 =

5 + 9 = 7 + 7 =

__Solution method__

Add up the numbers and fill in the blanks with the result.

__Solution guide__

a) 9 + 6 = 15 7 + 8 = 15 6 + 5 = 11

3 + 9 = 12 6 + 9 = 15 8 + 7=15

5 + 6 = 11 9 + 3 = 12

b) 3 + 8 = 11 4 + 8 = 12

2 + 9 = 11 6 + 7 = 13

5 + 8 = 13 4 + 7 = 11

5 + 9 = 14 7 + 7 = 14

**Lesson 2**

Calculate:

8 + 4 + 1 = 7 + 4 + 2 = 6 + 3 + 5 =

8 + 5 = 7 + 6 = 6 + 8 =

__Solution method__

Add the numbers in order from left to right.

__Solution guide__

8 + 4 + 1 = 13 7 + 4 + 2 = 13 6 + 3 + 5 = 14

8 + 5 = 13 7 + 6 = 13 6 + 8 = 14

**lesson 3**

__Solution method__

Add numbers in order from right to left.

__Solution guide__

**Lesson 4**

Mother picked 38 pomelos, she picked 16 pomelos. How many grapefruits did mom and sister pick in all?

__Solution method__

To find the number of pomelos that mother and sister picked, we take the number of pomelos she picked plus the number of pomelos she picked.

__Solution guide__

Mother and sister picked all the pomelos:

38 + 16 = 54 (grapefruit)

Answer: 54 grapefruits.

**Lesson 5**

Fill in the blanks with the correct number:

a) 5 … > 58; b) 89 < ... 8.

__Solution method__

a) Find the digit greater than 8 in the units row.

b) Find the digit greater than 8 in the tens.

__Solution guide__

a) 59 > 58; b) 89 < 98.

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