What is 26 plus 17 using the common core method using mental math to add?

To add 26 and 17 using the common core method with mental math, you can break the numbers into tens and ones. First, add the tens: 20 (from 26) plus 10 (from 17) equals 30. Next, add the ones: 6 (from 26) plus 7 (from 17) equals 13. Finally, combine the two results: 30 plus 13 equals 43. Thus, 26 plus 17 equals 43.