Can you tell me how to calculate the fractional division when the divisor is an integer?

Divider is a fractional division of integers.

Learning focus: be able to calculate fractional division with divisor as integer and master the calculation rules.

Learning difficulty: Adding "0" and integer part is not enough to quotient "1".

Learning process:

Step 1: Review and pave the way.

1. Rewrite the following figures to three decimal places.

4.2 0.7 1 3.56 3 (please explain the basis of rewriting)

2. Calculate the following questions.

45.6÷8 9. 12÷6

Question: How to calculate fractional division with integer divisor? Note: According to the law of integer division, the decimal point of quotient should be aligned with the decimal point of dividend.

3. Reveal the topic and write it on the blackboard

Two. New teaching course

1. Teaching Example 2.

(1) What is the fractional division of this problem? Can you work it out?

(Students try to do it, and one person performs on the board)

Where are you? What's the difference from the calculation in the last lesson?

Guide the students to observe: How much is left except ten? How many points is 12?

Is there any way to add a number at the end of "12", keep this number unchanged and continue to divide? Why can I add "0"? What does 120 mean after adding "0"? (blackboard writing)

How to divide it next? Let the students finish the problem.

Who can tell me the difference between Example 2 and the previous division problem? How to continue counting?

Point out that there is a remainder at the end of the multiplicand, and add "0" after the remainder to continue the division. (Show conclusion)

(2) Students practice 66.08÷32

Pay attention to ask why the quotient "0" is in the tenth place and how to divide it with the last remainder.

2. Teaching example 3.

(1) Read the formula. Question: Who is greater than the divisor? Is 36 divided by 48 enough quotient 1?

Note: In this case, the quotient should be the fraction of the fraction. Writing 0 in each bit means that the quotient is a decimal less than 1, which is different from integer division.

Question: How can we keep the size of the multiplicand unchanged and continue the division?

Follow-up: Can you just add a 0 and write it as 360 to divide it? Why?

Note: 36 is an integer, and you can't directly add 0 at the end. In order to keep the size of the multiplicand unchanged and continue the division, we must first place the decimal point at the lower right of unit 6, then add 0 (blackboard writing) after it, and then divide it by 360/10.

Can you get rid of it now? Students do it in their exercise books and one person acts it out.

Please use multiplication to check. Q: What did the inspection result show?

Question: What is the difference between Example 3 and the previous calculation? What if an integer is divided by an integer and the integer part is not quotient 1? What is the next step?

It is pointed out that in fractional division, if the multiplicand is less than the divisor and the integer part is not enough to quotient 1, then you must first write 0 on the quotient unit. (Show the conclusion) After the unit quotient is 0, the decimal point should be added at the end of the multiplicand, and 0 should be added to continue the division.

(2) Exercise 9. 12÷ 19 57÷750

3. induction.

Question: From last lesson's example 1 to today's example 2 and example 3, can you tell us what is the calculation method of fractional division when the divisor is an integer?

Let the students read the calculation rules.