Problem Solving

Parts Substitution

Perhaps the most basic of all the problem-solving methods, “parts substitution” simply
requires that parts be substituted until the problem is solved. Although it is not the most
scientific method of problem solving, there may be no other alternative if tests do not
indicate what could be causing the problem.


An example of a diagnostic problem-solving method is troubleshooting an engine fault in
an automobile. After identifying the general problem, the technician would run tests to
pinpoint the fault. The test results would be used either as a guide for further testing or
for replacement of a part, which would also need to be tested. This process continues
until the solution is found and the car is running properly.

Reverse Engineering

Reverse engineering is the process of discovering the technological principles underlying
the design of a device by taking the device apart, or carefully tracing its workings or its
circuitry. It is useful when students are attempting to build something for which they
have no formal drawings or schematics.

Divide and Conquer

“Divide and conquer” is the technique of breaking down a problem into subproblems,
then breaking the subproblems down even further until each of them is simple enough to be solved. Divide and conquer may be applied to allow groups of students to tackle subproblems of a larger problem, or when a problem is so large that its solution cannot be visualized without breaking it down into smaller components.

Extreme Cases

Considering “extreme cases” – envisioning the problem in a greatly exaggerated or greatly simplified form, or testing using an extreme condition – can often help to pinpoint a problem. An example of the extreme-case method is purposely inputting an extremely high number to test a computer program.

Trial and Error

The trial-and-error method involves trying different approaches until a solution is found.
It is often used as a last resort when other methods have been exhausted.

The Design Process

In many technological fields, open-ended problem-solving processes that involve the full
planning and development of products or services to meet identified needs are often
referred to as the “design process”. A design process involves a sequence of steps, such as
the following:

  • Analyse the context and background, and clearly define the problem or challenge.
  • Conduct research to determine design criteria, financial or other constraints, and
    availability of materials.
  • Generate ideas for potential solutions, using processes such as brainstorming and
  • Choose the best solution.
  • Build a prototype or model.
  • Test and evaluate the solution.
  • Repeat steps as necessary to modify the design or correct faults.
  • Reflect and report on the process.


“Technological Education: the Ontario Curriculum, Grades 11 and 12,
2009.” Technological Education: the Ontario Curriculum, Grades 11 and 12, 2009,
The Ministry of Education, 2009, pp. 22–23.