Children learn addition and subtraction well within 10, but they are confused about subtraction outside 10. For example, 2 1-9, teach him to borrow subtraction, the child is very confused, what is borrowing? Why borrow it? Very annoying, how to make children understand the knowledge points of borrowing subtraction.
The borrowing problem in subtraction reflected by this parent is a common problem that children will encounter in two-digit subtraction.
Children can't understand what borrowing is. On the one hand, I don't understand the "bits" in the carry system, on the other hand, I don't have a thorough grasp of the sum of points and numbers of logarithm.
Borrowing subtraction, also called abdication subtraction. It means that when two numbers are subtracted and the number of digits to be subtracted is not enough, the previous number is borrowed as ten, which is equivalent to adding 10 to calculate.
Generally speaking, when children don't know how to borrow subtraction, we advise parents not to rush to expand to a larger number.
Because increasing the difficulty can't improve children's math level, it will make children more confused and tired of learning.
Parents are advised to start subtraction from below 20, and try to let children accept and understand it slowly.
The following five methods are of great help to children's borrowing subtraction, and can also appropriately reduce the burden and anxiety of parents.
Counting stick Counting stick is a common teaching aid in mathematics teaching, which is usually used for digital counting.
For subtraction within 20, you can use a counting stick and use food to help children understand.
According to the requirements of the topic, count the corresponding number of counting bars, remove or add a certain number of counting bars, and then count to get the result.
If children find the counting stick too boring, they can also use their imagination to put numbers or their favorite shapes on it. The process is interesting and interactive. The key is to make children fall in love with this math learning method, which is very beneficial.
Drawing circles in kind is our first choice to teach children addition and subtraction. After the physics stage, we will move on to writing and painting-drawing a circle.
When children don't need to count points one by one with their fingers in the face of addition and subtraction, drawing a circle formula is an abstract and concrete method. Subtract two numbers, you can draw the cycle number corresponding to the minuend, then cross out the minuend part, and then count the rest, and it is the result.
The advantage of circle subtraction is that children can also use it in exams, because there are no tools to use in exams, so drawing a circle is also an important method.
Drawing the number axis takes the number axis as a tool, and the numbers are arranged in a certain interval order along the horizontal axis, increasing to the right, and vice versa.
By learning addition and subtraction with the number axis, children can not only get rid of direct operation in kind, but also operate logarithm in a wider range.
At the same time, the number axis makes the results obtained by children more intuitive, simpler, easier to master and understand, and more in line with children's cognitive understanding.
The minuend decomposition method is to decompose the minuend within 20 into two parts, namely, decomposition 10 and several, subtract the number obtained after subtraction with 10, and add several to the decomposed number to get the result.
Taking 17-9 as an example, the minuend 17 is divided into 10 and 7, where 10-9= 1, 1+7=8. In this way, it is very easy to understand and not easy to make mistakes by using the meiosis method for subtraction calculation, which is conducive to the development of oral calculation.
The method of meiosis is to divide meiosis into two parts, one of which has the same unit number as meiosis. Subtract single digits last night, and then subtract ten digits.
Take 13-8 as an example, divide the subtrahend 8 into two numbers, one of which is the same as the third bit of 13, that is, divide 8 into 3 and 5, 13-3= 10, and then use 10-5=5. This is similar to the minuend decomposition method.
The above five methods are simpler, easier and easier for children to accept and understand.
If your child doesn't understand or understand borrowing subtraction, you can try these methods.
Of course, if you have a simpler method, you are welcome to discuss it with us.