Student's Handbook of Mathematics, Physics, and Chemistry Formulas, Concepts, and Laws

Author: Liu Tianzhang
Publisher:
Publish Date: 2003-08-01
Features: This manual is compiled according to the current secondary school mathematics and physics teaching syllabus, following the order of the textbooks. It includes all important concepts, formulas, theorems, and laws from the textbooks. The manual has a standardized format and logical arrangement, making it convenient for readers to consult and memorize.
3. Multiplication Rule
(1) When multiplying two numbers, if they have the same sign, the result is positive; if they have different signs, the result is negative. Multiply their absolute values.
(2) Any number multiplied by 0 is 0.
(3) When multiplying several numbers that are not zero, the sign of the product is determined by the number of negative factors. If there is an odd number of negative factors, the product is negative; if there is an even number of negative factors, the product is positive.