Interesting math:
The animal mathematics group is having a heated discussion!
Cong Cong, the little monkey, asked a question: "When calculating addition and subtraction, the calculation starts from the low position. Why do you want to divide from high digits? "
Hearing this, the students all thought about it. The little squirrel thought, that's how the calculation method is stipulated. Any questions? The deer thought: can division be calculated from the low position like addition and subtraction? No one can find the right answer.
Seeing everyone's doubts, Teacher Goat first praised Cong Cong, a little monkey, as a thoughtful student, and then patiently explained, "Let's explain the truth from a simple division problem. Divide 30 carrots equally among 6 white rabbits. How many can each white rabbit get? " Little Nutbrown hare jumped up and said, "Great! 30÷6=5 (root), and each white rabbit is divided into 5 on average. " Teacher goat said, "Yes, then how do you suggest we divide it?" The elephant scrambled to say, "First, take out 6 out of 30 and give them to 6 white rabbits, and each white rabbit will give them1;" Then take out six to six white rabbits, and each white rabbit gives1; In this way, it will be finished in just five times. "Teacher Goat went on to say," If we use a formula to express the process of division just now, that is, 30-6-6-6 = 0, that is, take out six of the 30 just finished five times. However, it's too much trouble to pick up. Later, people used division to calculate such a problem: 30÷6=5 (root), which is much simpler, so division can also be regarded as a simple calculation of subtracting the same number continuously. "
"oh! No wonder subtraction is indispensable when calculating vertical division! " The elephant said to himself.
"Teacher, I still don't understand why division should be calculated from a height." Said the pig.
"I know." The little monkey Congcong scrambled to say, and ran to the blackboard to write as he spoke.
"For example, 205÷5 can be seen as 205 subtracting 5 continuously, and how many times it is subtracted to get 0."
205-5-5-……-5=0
Subtract 4 1 5 to get 0.
Little monkey Cong Cong finished writing and said, "205÷5 equals 4 1."
Teacher goat went on to say, "it's very troublesome to do subtraction, but it's much easier to use division." Look at the vertical type below:
4 1
5 2 0 5
20 ... subtract 40 fives first, and it's 200.
five
5 ... negative 1 5 is 5.
In the calculation process, we subtract 40 fives first, then 1 fives, and one * * * subtracts 4 1 fives to get 0, so the quotient is 4 1. "
The elephant understood and said, "Subtract from the high position and you can work it out quickly."
Teacher Goat added: "If there are a lot of calculations, you can clearly see the advantages of calculating division from high places. Students can try it themselves after class. "
After the discussion of small animals, everyone understood that division should start from the high position. Dear children, do you understand?
Question 2: Why is division calculated from a height? This is mainly done according to the basic operating rules.
Because multiplication starts from the low position and slowly rises to the high position.
Division is equivalent to the inverse algorithm of multiplication, and naturally it starts from the high position.
Question 3: Why should the vertical calculation of division start from the highest bit of divisor?
Question 4: "Can the teacher count the historical gains from top to bottom, successfully break the traditional four arithmetic rules and create a fast calculation method from top to bottom without using calculation tools?
Shi Fengshou, who lives in Dali County, Shaanxi Province, loves to think independently and dare to think and do since childhood. Once, when the teacher talked about multiplying one digit by multiple digits, he suddenly raised his hand and asked, "Teacher, can you count from top to bottom?" The teacher exclaimed, "You can invent if you are interested!" "10-year-old Shi Fengshou opened his wings of imagination and made up his mind to get out of the box of traditional algorithms. He plunged into the ocean of mathematics, writing and writing whenever he had time, using one calculus book after another and doing thousands of formula problems, but the answers were always wrong. One day, he suddenly got inspiration from this plan. When he multiplied by two times five, he removed five and made progress in the front position. His heart lit up, and the difficulty of thinking day and night suddenly lit up.
One day, a former accountant said, "Although the one-digit speed algorithm you created is good, the calculation is multiple digits by multiple digits!" " "Hearing this, Shi Feng accepted the determination. After countless days and nights of hard study, he finally solved the problem of multi-digit multiplication by "outward migration method" and conquered the fortress of fast division and subtraction. Shi Fengshou was invited to perform all over the country, and people were amazed at his quick calculation. Later, Shi Fengshou was admitted to the university, and with the help of relevant professors, the problem of taking prescriptions was quickly solved. The system reveals the law of "carry" and "addition" from the high position, and summarizes a set of fast calculation formulas. /kloc-addition, subtraction, multiplication, division and square within 0/3 digits, he can give the answer in one breath, faster than a calculator. Shi Fengshou said that quick calculation is the wealth of people all over the world and should be enjoyed by resources. He is willing to work for mathematics.
Question 5: When dividing with a pen, divide from the high-order dividend _ _ _ _ according to the stem analysis, and divide from the high-order dividend when dividing. The original question is correct, so the answer is: √.
Question 6: Why do you want to divide the division from a high position? "If the amount of calculation is large, it can be clearly seen from the high position that the calculator is fast ..."
Interesting math:
The animal mathematics group is having a heated discussion!
Cong Cong, the little monkey, asked a question: "When calculating addition and subtraction, the calculation starts from the low position. Why do you want to divide from high digits? "
Hearing this, the students all thought about it. The little squirrel thought, that's how the calculation method is stipulated. Any questions? The deer thought: can division be calculated from the low position like addition and subtraction? No one can find the right answer.
Seeing everyone's doubts, Teacher Goat first praised Cong Cong, a little monkey, as a thoughtful student, and then patiently explained, "Let's explain the truth from a simple division problem. Divide 30 carrots equally among 6 white rabbits. How many can each white rabbit get? " Little Nutbrown hare jumped up and said, "Great! 30÷6=5 (root), and each white rabbit is divided into 5 on average. " Teacher goat said, "Yes, then how do you suggest we divide it?" The elephant scrambled to say, "First, take out 6 out of 30 and give them to 6 white rabbits, and each white rabbit will give them1;" Then take out six to six white rabbits, and each white rabbit gives1; In this way, it will be finished in just five times. "Teacher Goat went on to say," If we use a formula to express the process of division just now, that is, 30-6-6-6 = 0, that is, take out six of the 30 just finished five times. However, it's too much trouble to pick up. Later, people used division to calculate such a problem: 30÷6=5 (root), which is much simpler, so division can also be regarded as a simple calculation of subtracting the same number continuously. "
"oh! No wonder subtraction is indispensable when calculating vertical division! " The elephant said to himself.
"Teacher, I still don't understand why division should be calculated from a height." Said the pig.
"I know." The little monkey Congcong scrambled to say, and ran to the blackboard to write as he spoke.
"For example, 205÷5 can be seen as 205 subtracting 5 continuously, and how many times it is subtracted to get 0."
205-5-5-……-5=0
Subtract 4 1 5 to get 0.
Little monkey Cong Cong finished writing and said, "205÷5 equals 4 1."
Teacher goat went on to say, "it's very troublesome to do subtraction, but it's much easier to use division." Look at the vertical type below:
4 1
5 2 0 5
20 ... subtract 40 fives first, and it's 200.
five
5 ... negative 1 5 is 5.
In the calculation process, we subtract 40 fives first, then 1 fives, and one * * * subtracts 4 1 fives to get 0, so the quotient is 4 1. "
The elephant understood and said, "Subtract from the high position and you can work it out quickly."
Teacher Goat added: "If there are a lot of calculations, you can clearly see the advantages of calculating division from high places. Students can try it themselves after class. "
After the discussion of small animals, everyone understood that division should start from the high position. Dear children, do you understand?
Question 7: Why is division calculated from a height? This is mainly done according to the basic operating rules.
Because multiplication starts from the low position and slowly rises to the high position.
Division is equivalent to the inverse algorithm of multiplication, and naturally it starts from the high position.
Question 8: Why should the vertical calculation of division start from the highest bit of divisor?
Question 9: Why should division be divided from the high order and multiplication from the low order? Because multiplication will have multiple digits, you need to input one digit, and division can borrow the next digit.
Question 10: Why does addition, subtraction, multiplication and division start from the lowest place? What if? Is division the highest? In fact, addition, subtraction, multiplication and division can also be calculated from the high position, and it is also calculated from the high position in the quick calculation, but we are used to counting from the low position when we start counting from primary school.