Inside the rectangle $ABCD$ is taken a point $M$ such that $\angle BMC + \angle AMD = 180^o$. Determine the sum of the angles $BCM$ and $DAM$.
1. **Reflect point \( M \) over the midsegment of rectangle \( ABCD \) to get point \( M' \).**
   - The midsegment of a rectangle is the line segment that connects the midpoints of two opposite sides. In this case, we can consider the midsegment connecting the midpoints of \( AB \) and \( CD \).

2. **Let \(\angle AMD = \theta\).**
   - Given that \(\angle BMC + \angle AMD = 180^\circ\), we have \(\angle BMC = 180^\circ - \theta\).

3. **Let the intersection point of \( M'A \) and \( BM \) be \( X \).**
   - By the properties of reflections, \( MX \) and \( M'X \) have equal lengths. Therefore, \(\angle MXM' = \theta\).

4. **It follows that \(\angle XAB = 90^\circ - \frac{\theta}{2}\).**
   - Since \( \angle XAB \) is part of the right triangle formed by the reflection, we can deduce that \(\angle XAB = 90^\circ - \frac{\theta}{2}\).

5. **This means that \(\angle M'AD = \angle M'DA\).**
   - By the properties of the reflection and the symmetry of the rectangle, \(\angle M'AD = \angle M'DA\).

6. **This means that \( M'A = MD \) and by symmetry, \( M'B = M'C \).**
   - Since \( M' \) is the reflection of \( M \) over the midsegment, the distances from \( M' \) to the vertices of the rectangle are equal to the distances from \( M \) to the opposite vertices.

7. **We can then find the answer of \(\boxed{90}\) from angle chasing.**
   - By considering the angles formed by the reflection and the properties of the rectangle, we can deduce that the sum of the angles \( \angle BCM \) and \( \angle DAM \) is \( 90^\circ \).