Calculeaza ținând cont de legătură dintre adunare și scadere
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The explanation is given below:

Step-by-step explanation:

The computation is shown below:

If we add 7 and 2 then it provides 9 and then subtract 2 from 9 it provides 7 and then subtract 7 from 9 it provides 2 and like this way it follows for others two

7 + 2 = 9

9 - 2 = 7  

9 - 7 = 2

8 - 3 = 5  

5 + 3 = 8

8 - 5 = 3

3 + 7 = 10  

10 - 7 = 3  

10 - 3 = 7