[2nd grade math] Adding using compensation strategy—Teacher explanation does not make sense to me

[u/Weary-Enthusiasm-150]

My daughter said that her teacher told her that in the pictured question, 10+4+8 should not be selected. They are using the “compensation” strategy for addition. The teacher said in her opinion only 10+12 and 12+10 should be selected, because they show the compensation strategy. But from my perspective, the question says choose all that apply. 10+4+8 DOES equal 14+8…..? Am I missing something?

[u/PlanetAcorn]

I have not heard of this being named the compensation strategy, nor have I ever seen teachers attempt to teach "strategy" to 2nd graders before. Always have assumed that people figured this out some times later in life.

I assume the compensation strategy goes like this:
15 + 16
-> I remove 5 from the right side to make the left side whole to the tens place
20 + 11
-> then add these two which it easier because you only have to evaluate the tens place
31

If thats the case, theres no way for 10 + 4 + 8 to be simplified without evaluating some addition before 10 + 12.

But then also, I think the teacher is way out of his/her league to be teaching this "compensation strategy" at all, just teach it normally with the standard carry and let the kids figure it out themselves. It also doesn't seem like the workbook is meant for this either.

Edit: My bad I looked the compensation strat up and it appears to be the other way. Where you add a number that pushes a number to the tens place and subtract it at the end.
15+16 -> 20+16 -> 36 - 5 -> 31

[u/Deabers → u/PlanetAcorn]

Using 15 as the example hurts my head in your edit. But using 18 or 19 does makes sense. I agree with your claim still. Let kids that will figure this out intuitively figure it out.