Because the first-grade primary school students are familiar with the addition and subtraction within 10, they use the method of breaking ten to calculate. For example, for the question of 13-6, first divide 13 into 3 and 10, then subtract 6 from 10, and then add the 4 from 10-6 with the previous 3 to get the answer.
Decimal method: As the name implies, it is to add two numbers first, and the result is 10. This is a simple operation that children can easily accept. For example: 6+9= 15, 9 can be divided into 4 and 5, first 6+4= 10, and then 10+5= 15.
This method is the most time-saving, but also the most difficult. Children should not only be proficient in carry addition within 20, but also have certain reasoning ability and reverse thinking ability.
Introduction to breaking ten methods:
Decimal method: a mathematical calculation method, that is, when the number of digits is not reduced enough, subtract the subtraction with 10 and add the remainder to the number of digits, that is, decimal method. Often abbreviated as math or maths, it is a discipline that studies concepts such as quantity, structure, change, space and information.
Mathematics is a universal means for human beings to strictly describe the abstract structure and mode of things, and can be applied to any problem in the real world. All mathematical objects are artificially defined in essence. In this sense, mathematics belongs to formal science, not natural science.
Different mathematicians and philosophers have a series of views on the exact scope and definition of mathematics. Mathematics plays an irreplaceable role in the development of human history and social life, and it is also an indispensable basic tool for studying and studying modern science and technology.