1, proficient in single-digit subtraction
In the subtraction within twenty, it is very important to master the single digit subtraction skillfully. This means that you need to be able to subtract single digits quickly and accurately. For the number 17 minus 9, you can split 17 into 10 and 7, and then subtract 9 from 7 to get -2. Finally, add -2 to 10 to get 8 and get the answer.
2. Understand the basic principle of subtraction.
Subtraction is a basic mathematical operation, and its principle is that subtracting a number is equivalent to adding the reciprocal of this number. Subtracting 5 is equivalent to adding -5. So subtraction can be converted into addition for calculation. In this way, the answer can be obtained through simple calculation.
3. Master the borrowing method.
When the minuend is less than the minuend, you need to borrow money. Borrowing means borrowing a "1" from ten digits, converting it into single digits 10, and then adding it to the minuend. For the number 16 minus 27, you can split 16 into 10 and 6, and then add 6 and 27 to get 33. Finally, subtract 10 from 33 to get 23 and get the answer-14.
4. Master continuous subtraction.
Continuous subtraction refers to the continuous use of subtraction in an expression. This operation can be carried out by splitting numbers and converting subtraction into addition. For Equation 32 minus 45 minus 2 1, you can first calculate 32 minus 45 to get-13, and then subtract 2 1 from-13 to get -34. In this way, you can get the answer-34.
Relationship between reciprocal sum of addition and subtraction operations and its application
1, addition and subtraction are reciprocal operations.
Addition and subtraction are the basic operations in mathematics, and there is a reciprocal relationship between them. Subtracting a number from a number is equivalent to adding the reciprocal of that number. 10 minus 3 can be regarded as 10 plus -3 to get 7.
2. The relationship between addition and subtraction in application.
When solving practical problems, we often choose addition and subtraction according to the needs of the problem. When calculating the difference between two numbers, use subtraction; When calculating the sum of two numbers, addition is used. In addition, addition and subtraction are also widely used in daily life, such as calculating change, calculating time difference and temperature difference when shopping.