B1.1 Approaches to computational thinking: notes and practice

What you need to know

Our summary of the topic in our own words, not the IB guide.

• Turn a vague problem statement into a precise problem specification
• State the inputs, outputs, constraints and assumptions of a problem
• Write success criteria that can actually be tested
• Apply decomposition to break a problem into sub-problems
• Apply pattern recognition to spot repetition and reuse across sub-problems
• Apply abstraction to hide detail that does not matter for the problem
• Describe levels of abstraction and move between a high-level view and a detailed one
• Design an algorithm as an ordered sequence of unambiguous steps
• Apply the full computational thinking process to an unfamiliar problem and produce a plan
• Read a flowchart and state what the algorithm it describes does
• Trace a flowchart with given inputs and produce the correct output, using a trace table
• Draw a flowchart for a described algorithm using the correct symbols for sequence, selection and iteration

Learn it

• The counting pattern

  Lesson with 2 exercises

• Read and trace a loop flowchart

  Lesson with 2 exercises

Practice questions

Original questions written for the 2027 course, marked as you go. Easiest first.

• Flowchart power of twoWritten · Core
• Decomposing a cinema booking systemWritten · Core
• Flowchart oddsWritten · Core
• Seats togetherCoding · Stretch

Exam tips for B1.1

• Trace flowcharts with a trace table, one row per step, so you do not lose track of values.
• Use the standard flowchart symbols for decisions, processes and input or output.
• Write success criteria that someone could actually test.