2. Let children know the structure of two digits, and distinguish between "ten digits" and "unit digits", such as "14", including a "10" and a "4", especially the "1" of ten digits, and understand that it stands for "/kloc-0".
3. The operation of two digits is suitable for the combination of "horizontal" and "vertical". The relationship between vertical ten digits and unit digits is more obvious. Instead of telling these "terms" to children, let them understand them through sensibility.
algorithm
When two numbers are added, every time the result of a certain bit is greater than or equal to 10, you need to count 1 to the next bit, which is the carry.
48
+ 56
————
= 104
8+6 = 14 & gt; 10 rises by one place (ten places) to 1.
4+5 plus rounded 1, that is, 4+5+ 1= 10 also needs to be rounded up by one bit (ten bits) to 1.
When there is carry addition in the operation, it is called "carry addition".