Open Middle®
Directions: Using the digits 0 to 9, at most one time each, place a digit in each box to make the angles add up to be 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?
How might the number of boxes for the addends tell us?
Answer
There are many possible answers. One example is: 42 + 138, 57 + 123, 48 + 132
Consider having students have a more approximate angle measure after finding a solution
Source: Catherine Castillo
8 dime
20 penny
20 pennies 8 dime
100 penny + 40 dime + 4 penny
16 solutions:
23° + 157° = 180°
24° + 156° = 180°
26° + 154° = 180°
27° + 153° = 180°
32° + 148° = 180°
38° + 142° = 180°
42° + 138° = 180°
48° + 132° = 180°
53° + 127° = 180°
54° + 126° = 180°
56° + 124° = 180°
57° + 123° = 180°
72° + 108° = 180°
74° + 106° = 180°
76° + 104° = 180°
78° + 102° = 180°
121 plus 59 equals 180
23 degrees + 157 degrees = 180
78+102=180