Open Middle®
Directions: Using the digits 0 to 9 at most one time each, place a digit in each box to make a true statement about these angles that add up to a straight angle. *Note: drawing not to scale.
Hint
What do you know about acute angles? How might the number of boxes for the addends tell us?
Answer
Ex: 42 + 138, 57 + 123, 48 + 132, many possible answers – consider having students have a more approximate angle measure after finding a solution
Source: Catherine Castillo
