Question

give an example of addition problem in which you would and would not group the addends differently to add

Answer 1

An example of a problem where I would not group the addends differently is:

3+2+4.

An example of a problem where I would group the addends differently is:

2+5+8.

Explanation:

In the first problem, I would not group the addends differently before adding.  This is because I cannot make 5 or 10 out of any of the numbers.  We group addends together to make "easier" numbers for us to add, such as 5 and 10.  If we cannot do that, there is no reason to regroup the addends.

In the second problem, I would regroup like this:
2+8+5

This is because 2+8=10, which makes the problem "easier" for us to add.  Since we can get a number like this that shortens the process, we can regroup the addends.

Answer 2

In a problem like 1+1+1, I would not group the addends differently. This is because, no matter which way you place the ones, you will always be adding 1+1+1.

In a problem like 3+5+7, I would group the addends differently (3+7+5). This is because, in the first problem you would first add together 3+5 to get 8, and then you would add 8+7 to get 15. However, if you were to add 3+7 first, you would get 10. 10+5 is much easier to add than 8+7.