1. Adding together

2. Let’s begin
探究一
探究二

3. What can you see in this picture?
探究一
探究二

4. 2 + 4 = 6
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探究二

5. 4 + 2 = 6
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探究二

6. addend 2 + 4 = 6 4 + 2 = 6 Do you know the name of every part? addend
= = 6
addend
addend
sum
Do you know the name of every part?
探究一
探究二

7. Calculate the sum of two parts,we can use addition.
Conclusion:
Calculate the sum of two parts,we can use addition.
探究一
探究二

8. What can you see in this picture? Can you tell the name of every part?
= 9
= 9
addend
addend
sum
探究一
探究二

9. Tell me what can you see in this picture? And then complete the formula.
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探究二

10. According to the colour: 2+7=9 7+2=9
探究二
According to the colour:
2+7=9
7+2=9
探究一
探究二

11. According to the position(up and down):
6+3=9
3+6=9
探究一
探究二

12. According to the position(left and right):
4+5=9
5+4=9
探究一
探究二

13. Notice these three groups of formulas,can you find out the secret?
Colour : = = 9
Up and down: = = 9
Left and right: = = 9
From different ways we can get different formula,but the answers are always the same.
探究一
探究二

14. 2+7= = =9
7+2= = =9
In each group,we can chang the first addend with the second one,the sum are the same.
探究一
探究二

15. Practice
练习一
练习二
练习三
练习四

16. Exercise 1
Tell a story according to the picture,and then complete the formula.
2+6=8
6+2=8
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练习二
练习三
练习四

17. Tell a story according to the picture,and then complete the formula.
Exercise 2
练习一
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练习三
练习四

18. According to the position： 5+2=7 2+5=7
Exercise 2
According to the position：
5+2=7
2+5=7
练习一
练习二
练习三
练习四

19. According to the colour： 4+3=7 3+4=7
Exercise 2
According to the colour：
4+3=7
3+4=7
练习一
练习二
练习三
练习四

20. Conclusion :
(1)To calculate the sum of two numbers ,we can use addition.
(2)We can change the place of two addends,and the sum will still be the same.