Subtraction is a basic mathematical operation used to calculate the difference between two numbers. For example, if you subtract 3 from 10, you can get 7 by subtraction.
The sign of subtraction is-,which means the difference between two numbers. Its basic principle is to subtract the second number from the first number to get the difference between them.
For example, if you want to subtract 3 from 10, you can subtract 3 from 10, that is, 10-3=7. Similarly, if you want to subtract 9 from 15, you can subtract 9 from 15, that is, 15-9=6.
In real life, subtraction is often used in various occasions, such as shopping change, time calculation and so on.
When performing subtraction, there are some basic rules and attributes that can help simplify the calculation process. The following are some common subtraction rules and attributes:
1, the commutative law of subtraction: For any real numbers A and B, the result of A minus B is equal to the reciprocal of B minus A ... that is, a-b = -(b-a). For example, 3 minus 2 gives 1, and 2 minus 3 gives-1.
2. The law of association of subtraction: For any real numbers A, B and C, the results obtained by subtraction in any order are the same. That is, (a-b)-c = a-(b+c). For example, (10 minus 5) minus 3 equals 2, and 10 minus (5 plus 3) equals 2.
3. The relationship between addition and subtraction: subtraction can be regarded as a special form of addition. For example, A minus B can be equivalently expressed as A plus B, which means that subtracting a number is equivalent to adding its reciprocal. For example, 10 minus 3 can be equivalently expressed as 10 plus (-3), and the result is still 7.
4. the relationship between zero and subtraction: the result of subtracting 0 from any number is equal to itself. That is, a-0 = a, such as 7 MINUS 0, the result is 7.
5. Elimination law of subtraction: For any real numbers A and B, when A minus A equals B minus the same number, the two numbers are equal. That is, if a-c = b-c, then a = b, for example, 5 MINUS 2 equals 3 MINUS 0, then both expressions get 3.
Matters needing attention in subtraction operation
1. Number sequence: When performing subtraction, please make sure to calculate according to the correct number sequence. The minuend should be before the minuend to ensure the correct difference.
2. Borrowing operation: When the subtrahend is greater than the minuend, borrowing operation is needed. In the borrowing operation, the borrowing number is readjusted from the high order to the low order of the subtraction. Ensuring the correct borrowing operation can avoid calculation errors.
3. Alignment of decimal points: When subtracting decimal points, ensure that the decimal points are aligned so that the corresponding numbers correspond. This ensures that the correct fractional difference is obtained.