The practical problem of finding out what a fraction of a number is

For multiplication problems, just multiply that number by a fraction.

1.Read the relative sentence over and over again to find out the number of "1".

1) The kilogram of cabbage is 2/3 of that of radish (2) 7/8 of the number of black rabbits is the number of white rabbits (3) The number of boys is 1/7 more than that of girls (4) The number of girls is 1/8 less than that of boys

2 In the following questions, which quantity should be regarded as the unit "1", and the relationship between the quantities should be written.

1) A batch of cement, 3/5 of which was used. (2) The number of buffalo heads is equivalent to 5/6 of the number of cattle heads, and (3) 2/3 of a pile of sand is carried away. (4) 7/10 of B is equivalent to A.

5) The number of pages of a book that has been read is 3/4 of the remaining pages.

Finding a fraction of a number more than a number is a practical problemTeaching objectives: to enable students to answer the application problem of "finding a fraction of a number more than a number"; To further develop students' ability to draw line diagrams, so as to improve students' proficiency in solving such practical problems. Teaching difficulties:

Learn to analyze quantitative relationships and solve practical problems correctly and skillfully. Teaching aids to prepare the moon melt the nest naked scoop De Expand Rice Fierce Uranium Horse Moment Xin Li Marry Ke Pan Ku Bait Xiao Lin Love Strong Burning Mourning Yang Pregnancy Driving Argument Shaving Shaving Forced Room Appliance It Swings Hard Paste Ji Su Shop Eggplant Trap New Eyelash Moxibustion Fan Tired Line Outside the Line Outside the Door Mourning Extravagance Teaching Objectives: Make students answer the practical problem of "find out how many fractions of a fraction more than a number"; To further develop students' ability to draw line diagrams, so as to improve students' proficiency in solving such practical problems.

Teaching difficulty: Learn to analyze quantitative relationships and solve practical problems correctly and skillfully. Preparation of teaching aids:

Wu Lanfang's Teaching Process: Case (1) Review Old Knowledge 1Complete Question 6 of Exercise 5 and connect the equations with equal results.

2.Name the unit "1" and the unit "1" is a fraction of the unit "1". The number of boys is 52 of the girls, 52 of the bottles of ink have been used, and the number of bottles of strawberry jam is 41 more than the number of bottles of salad dressing.

2) Teaching implementation 1Example 3, read the question in a group, understand the meaning of the question, and ask: "Baby every 2."

Instruct students to draw a picture How many times a baby's heartbeat per minute is equivalent to a teenager's heartbeat per minute? Method 1: 75 + 75 54 Method 2:

75 (1 +54) Invite students to describe the ideas for solving these two problems completely. 3.Deepen the exercise Complete the "do it" on page 21 of the textbook, and complete the question (3) of exercise 5 Designing class assignments Analyzing the relationship between quantities Xiaohong reads a book and has read 53 of the book, (is the unit "1", 53 means ( ) The number of pages not read is represented by ( ).

38 More flour than rice means that flour is equivalent to rice ( ) 4) Class Summary Today we have learned the practical problem of "finding what is the number of fractions more than a number", and to answer this kind of question, we must first find out the relationship between quantities, draw a line segment diagram, and then solve it. Reflection after class.

Find out what a fraction of a number is--- use this fraction of the number;

It is known how many fractions of a hail is a digital finch. This number = fractions of the product;

Such as: delayed. Find out what is 1 2 in 3 4. 3/4×1/2=3/8；

The number 3 4 of a number is 1 2, and this number = 1 2 3 4 = 1 2 4 3 = 2 3

How much"÷"A few fractions"= this number.

What is a fraction of a number? It is the product of this number multiplied by a fraction.

For example, if a number is 100, two-fifths of 100 is.

Answer: The fraction of a number is the product of the number multiplied by the fraction.

Of course, it is just a division calculation.

It is more commonly used in word problems.

A b of a number is c.

Then this number is c (a b).

Gets equal to BC A

To help you summarize this type of question, where it comes to fractions, let the actual value represented by the denominator be the mother number, and the actual value represented by the numerator is the number of subs, the basic formula is: the number of the denominator fraction = the number of subs.

Your problem is equivalent to the unknown number of the parent number, and the number of fractions and subnumbers are known, according to the formula has:

Number of Parent = Number of Children Score.