Broken Calculator Problems

Suppose you wanted to use a calculator to computer a certain problem. However, certain keys on the scientific calculator you have are broken. Find the solution to the following problems without using your broken keys:

  • Solve 31.2 + 5.14 if the 1, 2, 3, 4, and 5 keys are broken.
  • Solve 311.2 – 5.14 if the 1, 2, 3, 4, and 5 keys are broken.
  • Solve the problem 3.5 * 0.42 if the 2, 3, 4, and 5 keys are broken

(Source: “Learning number sense from a broken calculator” On-Math 2006, Volume 4, Number 1)

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