Current location - Training Enrollment Network - Mathematics courses - Stacking cup mathematics
Stacking cup mathematics
Since all seven cups need to be inverted, each cup needs to be inverted an odd number of times, so the number of times the seven cups turn must be odd (odd times 7 equals odd), so it is impossible to change the direction of six cups at a time so that all the cups face down. .

As for the five cups, we will number them as 1234567, 12345 for the first time and 23456 for the second time. At this time, turn over two cups, and the remaining 7-2=5 cups will be turned over at one time. .