Interval problem is also a common problem in senior one thinking training, and it is also a complicated problem for children.

"Kid, open your hand, five fingers, a few empty fingers? Please take a closer look. "

The "empty" here refers to the interval. A hand has five fingers and four spaces.

At this time, the interval number = hand index-1.

Let's look at a similar example:

Actually, it's very simple to do interval questions. Simply put, the number of intervals is equal to the total minus one. If you're not sure, that's all right. Just draw a schematic diagram on paper and it will be simple and clear.