Worked Examples and Scaffolding, Dept.

NOTE: I’m talking about understanding in math at the researchED conference in Vancouver on Feb. 9. See here.


In teaching procedures for solving both word problems and numeric-only problems, an effective practice is one in which students imitate the techniques illustrated in a worked example. (Sweller, 2006). Subsequent problems given in class or in homework assignments progress to variants of the original problem that require students to stretch beyond the temporary support provided by the initial worked example; i.e., by “scaffolding”. Scaffolding is a process in which students are given problems that become increasingly more challenging, and for which temporary supports are removed.  In so doing, students gain proficiency at one level of problem-solving which serves to both build confidence and prepare them for a subsequent leap in difficulty.  For example, an initial worked example may be “John has 13 marbles and gives away 8. How many does he have left?”  The process is simple subtraction.  A variant of the original problem may be: “John has 13 marbles.  He lost 3 but a friend gave him 4 new ones.  How many marbles does he now have?”  Subsequent variants may include problems like “John has 14 marbles and Tom has 5.  After John gives 3 of his marbles to Tom, how many do each of them now have?”

Continuing with the example of adding and subtracting, in early grades some students, particularly those with learning disabilities, have difficulty in memorizing the addition and subtraction facts.  On top of the memorization difficulties, students then face the additional challenge of applying this knowledge to solving problems. One approach to overcome this difficulty has been used for years in elementary math texts, in which students are provided with a minimum of facts to memorize and  then given word problems using only those facts the student has mastered. Such procedure minimizes situations in which working memory encounters interference and becomes overloaded as described in Geary (in press). For example, a student may be tasked with memorizing the fact families for 3 through 5.  After initial mastery of these facts, the student is then given word problems that use only those facts.  For example, “John has 2 apples and gets 3 more, what is the total?” and “John has some apples and receives 3 more; he now has 5 apples. How many did he have to start with?”  Additional fact families can then be added, along with the various types of problems.  Applying the new facts (along with the ones mastered previously) then provides a constant reinforcement of memorization of the facts and applications of the problem solving procedures. The word problems themselves should also be scaffolded in increasing difficulty as the student commits more addition and subtraction facts to memory.

Once the foundational skills of addition and subtraction are in place, alternative strategies such as those suggested in Common Core in the earlier grades may now be introduced.  One such strategy is known as “making tens” which involves breaking up a sum such as 8 + 6 into smaller sums to “make tens” within it. For example 8 + 6 may be expressed as 8 +2 + 4. To do this, students need to know what numbers may be added to others to make ten. In the above example, they must know that 8 and 2 make ten.  The two in this case is obtained by taking (i.e., subtracting) two from the six.  Thus 8 + 2 + 4 becomes 10 + 4, creating a short-cut that may be useful to some students.  It also reinforces conceptual understandings of how subtraction and addition work .

The strategy itself is not new and has appeared in textbooks for decades. (Figure 1 shows an explanation of this procedure in a third grade arithmetic book by Buswell et. al. (1955).

The difference is that in many schools, Common Core has been interpreted and implemented so that students are being given the strategy prior to learning and mastering the foundational procedures.  Insisting on calculations based on the “making tens” and other approaches before mastery of the foundational skills are likely to prove a hindrance, generally for first graders and particularly for students with learning disabilities.

Figure 1: Adding by “making tens” from Buswell, et. al. (1955)

Figure 1: Adding by “making tens” from Buswell, et. al. (1955)

Students who have mastered the basic procedures are now in a better position to try new techniques — and even explore on their own.  Teachers should therefore differentiate instruction with care so that those students who are able to use these strategies can do so, but not burden those who have not yet achieved proficiency with the fundamental procedures.

Procedure versus “Rote Understanding”

It has long been held that for students with learning disabilities, explicit, teacher-directed instruction is the most effective method of teaching.  A popular textbook on special education (Rosenberg, et. al, 2008) notes that up to 50% of students with learning disabilities have been shown to overcome their learning difficulties when given explicit instruction. The final report of the President’s National Math Advisory Panel (2008) states: “Explicit instruction with students who have mathematical difficulties has shown consistently positive effects on performance with word problems and computation. Results are consistent for students with learning disabilities, as well as other students who perform in the lowest third of a typical class.” (p. xxiii). These statements have been recently confirmed by Morgan, et. al. (2014). The treatment for low achieving, learning disabled and otherwise struggling students in math thus includes memorization and other explicit instructional  methods.

Currently, with the adoption and implementation of the Common Core math standards, there has been increased emphasis and focus on students showing “understanding” of the conceptual underpinnings of algorithms and problem-solving procedures. Instead of adding multi-digit numbers using the standard algorithm and learning alternative strategies after mastery of that algorithm is achieved (as we earlier recommended be done), students must do the opposite. That is, they are required to use inefficient strategies that purport to provide the “deep understanding” when they are finally taught to use the more efficient standard algorithm. The prevailing belief is that to do otherwise is to teach by rote without understanding.  Students are also being taught to reproduce explanations that make it appear they possess understanding — and more importantly, to make such demonstrations on the standardized tests that require them to do so.

Such an approach is tantamount to saying, “If we can just get them to do things that look like what we imagine a mathematician does, then they will be real mathematicians.” Forcing students to think of multiple ways to solve a problem, for example, or to write an explanation for how they solved a problem or why something works does not in and of itself cause understanding. It is investment in the wrong thing at the wrong time.

The “explanations” most often will have little mathematical value and are naïve because students don’t know the subject matter well enough. The result is at best a demonstration of “rote understanding” — it is a student engaging in the exercise of guessing (or learning) what the teacher wants to hear and repeating it.   At worst, it undermines the procedural fluency that students need.

Understanding, critical thinking, and problem solving come when students can draw on a strong foundation of domain content relevant to the topic being learned. As students (non-LD as well as LD) establish a larger repertoire of mastered knowledge and methods, the more articulate they become in explanations.

While some educators argue that procedures and standard algorithms are “rote”, they fail to see that exercising procedures to solve problems requires reasoning with such procedures — which in itself is a form of understanding.  This form of understanding is particularly significant for students with LD, and definitely more useful than requiring explanations that students do not understand for procedures they cannot perform.


Ansari, D. (2011). Disorders of the mathematical brain : Developmental dyscalculia and mathematics anxiety. Presented at The Art and Science of Math Education, University of Winnipeg, November 19th 2011.

Buswell, G.T., Brownell, W. A., & Sauble, I. (1955). Arithmetic we need; Grade 3.  Ginn and Company. New York. p. 68.

Geary, D. C., & Menon, V. (in press). Fact retrieval deficits in mathematical learning disability: Potential contributions of prefrontal-hippocampal functional organization. In M. Vasserman, & W. S. MacAllister (Eds.), The Neuropsychology of Learning Disorders: A Handbook for the Multi-disciplinary Team, New York: Springer

Morgan, P., Farkas, G., MacZuga, S. (2014). Which instructional practices most help first-grade students with and without mathematics difficulties?Educational Evaluation and Policy Analysis Monthly 201X, Vol. XX, No. X, pp. 1–22. doi: 10.3102/0162373714536608

National Mathematics Advisory Panel. (2008). Foundations of success: Final report. U.S. Department of Education.

Rittle-Johnson, B., Siegler, R.S., Alibali, M.W. (2001). Developing conceptual understanding and procedural skill in mathematics: An iterative process. Journal of Educational Psychology, Vol. 93, No. 2, 346-362. doi: 10.1037//0022-0063.93.2.346

Rosenberg, M.S., Westling, D.L., & McLeskey, J. (2008). Special education for today’s teachers. Pearson; Merrill, Prentice-Hall. Upper Saddle River, NJ.

Sweller, P. (1994) Cognitive load theory, learning difficulty, and instructional design.  Leaming and Instruction, Vol. 4, pp. 293-312

Sweller, P. (2006). The worked example effect and human cognition.Learning and Instruction, 16(2) 165–169



7 thoughts on “Worked Examples and Scaffolding, Dept.

  1. This is an outstanding and succinct description of the bogus ‘better conceptual understanding’ assertion made by Common Core math supporters. The use of the term “rote understanding” is also an excellent (and apt) term for what kids have learned to do to in the Common Core classroom. We called it “parroting” as students learned to repeat back the explanations the teachers modeled with minor modifications, and very little real understanding. My kids became quite adept at parroting in elementary math classes. Another article that describes why the Common Core prescribed sequence of teaching “conceptual understanding” first to be followed by procedural practice is exactly backward given human cognitive architecture is “Cognitive Science and the Common Core Mathematics Standards” by Eric A. Nelson in NonPartisan Education Review (2017):


  2. I suspect that you are one of those people for whom rote memorization comes easily. It is difficult for you to believe that a child could have trouble with just memorizing their math facts. Trust me, a child can spend hours with flash cards trying to rote memorize their facts and still be unable to tell if 7 + 5 equals 12 or 13. The only reason for teaching about making tens is to help children with the more difficult math facts. Both Singapore and Shanghai maths use the making tens method beginning in first grade to help children learn their hard math facts. The idea that you would wait until a child had already learned their math facts by rote to introduce making tens makes no sense. If a student can recall all of the math facts by rote, and some children are very good at this, then there is no point in making tens. I work with students who have struggled for years trying to rote memorize their math facts. When I show them how to make tens, their first reaction is always, “Why didn’t my teacher tell me about this to begin with?” There is a reason why Singapore and Shanghai teach math this way.


    • Singapore does both; making tens is offered as a method, but doesn’t require students to do it for weeks on end. Yes, there are strategies for memorizing the math facts, but the idea that straight memorization without the strategy is eclipsing “understanding” is how people are framing the practice. As I say in the piece, “Teachers should therefore differentiate instruction with care so that those students who are able to use these strategies can do so, but not burden those who have not yet achieved proficiency with the fundamental procedures.” Insisting that all students use these procedures can hinder some–and Singapore does not insist upon it.

      And no, memorization did not come easy for me. But we had drills/quizzes just about every other day when I was in 2nd grade (which was when arithmetic started to be taught when I was in school), and by the end of the first semester, I had all the facts down.


      • Singapore math has children making tens for years. It starts in first grade and continues through the third grade. Both Singapore and Shanghai are known for their insistence on mastery learning. A child cannot pass the end of year tests without the ability to use what they call “number bonds”, a fluency in decomposing numbers that includes making tens but extends much further. This is not a frill. It is essential to the curriculum.


  3. In the Primary Math series, which is what I was going by, the making tens method is indeed introduced in first grade, but the problems that follow do not all require it. I, too, had making tens as my post indicates. It was introduced in 3rd grade in my case. My point is that the foundational mastery can support the alternatives and many times students discover these methods themselves. The point is that Singapore allows both standard algorithms/procedures and the alternate strategies. While they may test proficiency with both, they do not delay the teaching of the standard methods–both are practiced, whereas in the current interpretation of Common Core, there is a belief that students must show “understanding” first before being allowed to do the procedure. This goes beyond just the making tens method, but applies to multidigit addition and subtraction. As a result, the standard algorithms for multidigit add/subtract and multiplication are delayed until 4th and 5th grades, even though Common Core does not prohibit the teaching of the standard algorithms earlier, as verified by both Jason Zimba and Bill McCallum, co-writers of the Common Core math standards. See


  4. I’ll agree that in Singapore math the standard algorithms follow closely on the heels of conceptual presentations and that students are required to be proficient in both conceptual math and the standard algorithms.


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