Adding three or four single-digit numbers Mentally (2nd grade math)

In this 2nd grade lesson, we delve into mental addition of several single-digit numbers — sums such as 6 + 8 + 5 or 9 + 9 + 4 + 5 and similar. In adding four numbers, it often works to first add them in pairs. Another useful strategy in mental math is to add the tens, add the ones, and lastly combine the two sums.

In this lesson, we also compare sums (with the alligator mouths, once again :), solve a word problem involving Mathy, and lastly solve a PUZZLE problem — yes!