According to the authors of "Instead of Teaching Missing Addends", a 1998 article published in Teaching Children Mathematics, it is not necessary to give children formal instruction of missing addends, provided they are given other meaningful opportunities to develop numerical reasoning. This assertion is based upon research drawn from a study of 110 students in five classes of first graders located in two Alabama public schools. The students were never given formal instruction of missing addend problems, nor were they exposed to textbook or workbook math exercises. Instead, they were given opportunities to solve everyday math problems, such as playing games that involved adding money, adding numbers together on playing cards to get to a certain sum, and debating with classmates on how to solve word problems that pertained to everyday situations. Near the end of the school year the teachers of the five classes were asked to give their students a short test consisting of six missing addend problems.

Ninety-two percent of the students completed the test with no errors or only one error. Only eight of the 110 children demonstrated difficulty with the test. Still not having been exposed to formal instruction of missing addends, four of the eight children were re-tested a year later and demonstrated they were able to master the concept without formal instruction.

The authors found that the games were more effective in teaching the students the concept of missing addends simply because "children think very hard and from many viewpoints when they play games" (Kammi, 460). The games kept the children motivated and focused because they provided an element of exploration and challenge, elements that are absent in most worksheet and textbook activities. Also, the children were encouraged to use numerical reasoning in a variety of ways while playing the games, which...