* Addition and subtraction exercises within 5 (first grade, first volume);
* Addition and subtraction exercises within 10 (first grade, first volume);
* Addition and subtraction exercises within 100 (first grade, second grade, first volume);
* Addition and subtraction exercises within 10000 (third grade, first volume);
* Addition and subtraction exercises of decimals (fourth grade, second volume);
In addition, you can also generate targeted exercises including addition and subtraction exercises within 20, within 50, within 500, and within 1000; and, the addend/addend/subtrahend/minuend of the exercises can be composed of decimals, tens, hundreds, and thousands.
Key Points
1. The concept of addition and subtraction:
1 ) The algorithm of combining two or more numbers is called addition, which is one of the four basic arithmetic operations;For example: 3 + 5 = 8, where 3 is the augend, 5 is the addend; the augend and the addend can be swapped, and the sum remains unchanged;
2 ) The operation of subtracting one number from another is called subtraction, and subtraction is also one of the four basic arithmetic operations; for example: 5 - 2 = 3, where 5 is the minuend and 2 is the subtrahend, and the result 3 is called the difference;
2. Addition and subtraction symbols:
1 ) The symbol for addition is " + ";
2 ) The symbol for subtraction is " - ";
3. Understand addends and addends:
1 ) An addend is a number that participates in addition.
2 ) An augend is the number to which another number is added in addition.
When finding the sum of two numbers a and b, the first number a is called the augend, and the second number b is called the addend;
4. Understand subtrahends and minuends:
1 ) The minuend is the number from which another number is subtracted in subtraction.
2 ) The subtrahend is the number that is subtracted from the minuend in subtraction.
For example: Subtraction operation 8 - 6 = 2; 8 is the minuend, 6 is the is the subtrahend;
Minuend - subtrahend = difference, that is, the difference is obtained by subtracting the subtrahend from the subtrahend; the difference is the result of subtracting the subtrahend from the subtrahend;
The relationship between the subtrahend and the minuend is: minuend - subtrahend = difference; minuend - difference = subtrahend; subtrahend + difference = minuend;
5. Pen arithmetic addition and subtraction:
1 ) Integer addition: Align the numbers by their place values and start adding from the units place. If the sum of any place reaches ten, carry 1 to the next higher place.
2 ) Integer subtraction: Align the numbers by their place values and start subtracting from the units place. If any place does not have enough to subtract, borrow 1 from the next higher place, add it to the current place, and then subtract.
6. Digit and carry rules:
1 ) Digit refers to the position of a number in a number, indicating that the counting unit has ones, tens, hundreds, thousands, ten thousand... ..., any number composed of multiple digits has its own position, and this position is called a digit, for example: 5218, where "8" is in the ones place, "1" is in the tens place, "2" is in the hundreds place, and "5" is in the thousands place;
2 ) Carry is a form of operation. In the decimal system, when the number is full of ten, add one to the tens place; when the number is full of ten, add one to the hundreds place;
3 ) Borrow refers to the subtraction operation. When the number of a counting unit is not enough to subtract, it is necessary to borrow one from the high place to the low place, so that the low place subtrahend is added with 10, and then the subtraction operation is performed;
