The number of groups in the first grade of primary school is two arrays combined into a number, such as 1 and 2 to form 3, 7 and 5 to form 12 and so on. Through the study of the composition of numbers in Grade One, one is to strengthen the memory of logarithm and understand the relationship between numbers, and the other is to lay the foundation for learning addition and subtraction. For example, how to calculate 82? Students think that 8 and 2 make up 10, so they are equal to 10, or when calculating 7-2, they think that 2 and how many make up 7, and so on.