6×7=42 In Tian Zige, 6 and 7 should be aligned and written vertically to the right, and the multiplication sign should be between 6 and 7. 42 is directly below 6 and 7. Multiplication is the multiplication of letters with the same coefficient. For letters only contained in the monomial, they are used as factors of the product together with their indices.

Mathematics is a subject that studies concepts such as quantity, structure, change, space and information.