Can you talk about the addition and subtraction of two digits and hundreds of dozens?

Pay attention to the addition and subtraction of single digits and tens when adding and subtracting two digits and hundreds and tens.

The oral calculation of adding and subtracting hundreds and tens belongs to the addition and subtraction of three digits, that is, the addition and subtraction of one, ten and hundreds digits; The connection between the two is that the addition and subtraction of two digits is the only way to add and subtract three digits, and it will be easier to learn to add and subtract three digits if you learn to add and subtract two digits. Pay attention to the addition and subtraction of single digits and tens when adding and subtracting two digits and hundreds and tens.

The steps of adding and subtracting two digits are to add one digit first and then ten digits. When the sum of digits is ≥ 10, enter 1 in ten digits. When subtracting, subtract the single digits first. If it is not enough, borrow 1 from ten digits, and then ten digits. Pay attention to the alignment of the same digits when adding two digits; Starting with one digit, one digit is full of ten, and one digit is advanced to ten digits; When you subtract two digits from two digits, you should pay attention to the alignment of the same digits. If the number of digits to be subtracted is not enough, borrow 1 from the ten digits as ten, and then subtract.

Significance of adding and subtracting two digits from two digits

First of all, adding two digits to two digits is to combine two digits to get a bigger number. For example, if we add 23 and 34, we get 57. This means that 23 units and 34 units are merged, resulting in a total of 57 units.

Similarly, subtracting two digits from two digits means subtracting a smaller number from a larger number to get another number. For example, if we subtract 23 from 57, we get 34. This means subtracting 23 units from 57 units and we get 34 units.

In addition, these operations can also be used to solve practical problems. For example, if you have 34 apples and 23 apples and then you put them together, you will have 57 apples. Similarly, if you have 57 apples and give 23 to others, you will still have 34 apples left.

Generally speaking, the significance of two-digit addition and subtraction lies in the simplicity and practicability of operation, and it is a basic operation skill that must be mastered in mathematics learning.