Two adjacent integer tens before and after a number are adjacent integer tens of the number. Adjacent integers such as 20 are 10 and 30.

Adjacent number is a mathematical term, which means that in the natural numbers arranged from small to large, the two adjacent numbers before and after a number are the adjacent numbers of the number. Example: Like 5, the adjacent numbers of 5 are 4 and 6.

Integer decimal refers to the number between 10 and +∞ (positive infinity), which is often used for rounding when trading. Then adjacent integer tens, such as 10 and 20, are two adjacent integer tens. For example, the two integers adjacent to 10000 are 9990 and100/0 respectively.

The learning of adjacent numbers is a common learning progress in kindergartens in China. Based on the analysis of the age characteristics and present situation of large-class children, they are very interested in numbers and curious about the surrounding environment, so they can choose to let children understand the adjacent numbers of numbers.