Synthesis and decomposition of 8 can be divided into 1 and 7, and 1 and 7 can form 8; 8 can be divided into 2 and 6, and 2 and 6 can form 8; 8 can be divided into 3 and 5, and 3 and 5 can form 8; 8 can be divided into 4 and 4, and 4 and 4 can form 8; 8 can be divided into 5 and 3, and 5 and 3 can form 8; 8 can be divided into 6 and 2, and 6 and 2 can form 8; 8 can be divided into 7 and 1, 7 and 1 can form 8.

Composition and decomposition of 9 can be divided into 1 and 8, and 1 and 8 can form 9; 9 can be divided into 2 and 7, and 2 and 7 can form 9; 9 can be divided into 3 and 6, and 3 and 6 can form 9; 9 can be divided into 4 and 5, and 4 and 5 can form 9; 9 can be divided into 5 and 4, and 5 and 4 can form 9; 9 can be divided into 6 and 3, and 6 and 3 can form 9; 9 can be divided into 7 and 2, and 7 and 2 can form 9; 9 can be divided into 8 and 1, 8 and 1 can form 9;

Introduction to mathematics:

Mathematics [English: Mathematics, from ancient Greece μ? θξμα(máthēma)； 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 and deduce 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.

Mathematics originated from the early production activities of human beings, and the ancient Babylonians had accumulated some mathematical knowledge, which could be applied to practical problems. As far as mathematics itself is concerned, their mathematical knowledge is only obtained through observation and experience, and there is no comprehensive conclusion and proof, but their contribution to mathematics should also be fully affirmed.