Numberless Protractors
  • Print onto OHP transperency, 10 to a page
  • Easy to use
  • Provokes 'reasonableness of answer' approach to measuring angles
  • Requires users to count angles in 'lots of 10' and then estimate the last part of an angle
Angle Estimation sheet
Challenge students to estimate and record their answers first, and then use a 'Numberless Protractor' to measure each angle, calculate the error.
Using a timer will create some 'urgency' for students to complete the task quickly. IWB software has built-in protractors (typically, a traditional protractor) and the Maths 300 lesson Angle Estimation has some some useful software.
Screen dump of part of Angle Estimation sheet