A birthday cake was cut into equal pieces, and two pieces were eaten. The fraction below shows how many pieces were left. According to the fraction,
how many pieces were not eaten?
9
11
A. 13
B. 9
C. 2.
O
D. 11
O

If m∠abc = 70°, what is m∠abd? justify your reasoning.  using the addition property of equality, 40 + 70 = 110, so m∠abd = 110°.  using the subtraction property of equality, 70 − 30 = 40, so m∠abd = 30°.  using the angle addition postulate, 40 + m∠abd = 70. so, m∠abd = 30° using the subtraction property of equality.  using the angle addition postulate, 40 + 70 = m∠abd. so, m∠abd = 110° using the addition property of equality.