This kind of problem has a dotted line, but it is not clear from which side, so it is usually necessary to write two subtraction formulas. Both formulas count the total first, and then subtract the left part to get the right part-6-2 = 4; Subtract the right part from the total to get the left part -6-4 = 2.
Subtraction is one of the four operations, and the operation of subtracting one number from another is called subtraction; Given the sum of two addends and one of them, the operation of finding the other addend is called subtraction. The symbol of subtraction is "-",which is pronounced as negative sign.
Subtraction is a mathematical operation that represents the operation of removing an object from a collection. Its symbol is the minus sign (? )。 For example, in the picture on the right, there are five? Two apples, five apples, two were taken away, leaving three apples. So 5? 2=3。 Subtraction is to remove or reduce physical quantities and abstract quantities with different objects (including negative numbers, fractions, irrational numbers, vectors, decimals, functions and matrices).
Subtraction follows several important patterns. It is anti-commutative, which means that changing the order will change the sign of the answer. It is not associative law, that is, when a subtraction exceeds two numbers, the order of subtraction is very important.
Subtracting 0 does not change a number. Subtraction also follows predictable rules related to addition and multiplication. These laws can be proved, starting with the subtraction of integers and summarizing them with real numbers and other things. Continue the general binary operation of these patterns and learn in abstract algebra.
Unit of measure
When subtracting two numbers in kilograms or pounds, they must have the same unit. In most cases, the differences between them are the same as the original drawings.
per cent
The percentage change can be reflected in at least two forms, percentage change and percentage change. A percentage change represents a relative percentage change between two quantities, and a percentage change is a number obtained by subtracting two percentages.
For example, suppose that 30% of the components produced by the factory are defective. After six months, 20% of the products were defective. The percentage change is -33/3%, while the percentage change is-10 percentage point.