# CBSE Class 6 Maths Revision Notes Chapter 12

## CBSE Class 6 Mathematics Chapter 12 Revision Notes – Ratio and Proportion

Students must have learnt the concepts of multiplication and division in previous classes. Now, they need to apply these concepts to the chapter on Ratio and Proportion. Chapter 12 Ratio and Proportion in Class 6 Mathematics is an essential chapter for students as they will learn the fundamentals of each topic covered in the chapter and their applications.

The first section of Class 6 Mathematics Chapter 12 Notes will focus on the fundamental concepts of Ratio and Proportion. A ratio is a comparison of two entities of the same type. For example, the height of two buildings, the length of two garments, and the size of two playgrounds. If Samara’s age is 10 years and her father’s age is 30 years, how many times does the father’s age exceed Samara’s age? 3 is the obvious answer. A ratio is defined when two objects are compared in terms of ‘how many times’. The symbol ‘:’ represents the ratio.

When the two ratios are equal, we say that they are in proportion. As a result, four distinct entities are required to describe a proportion. A proportion is expressed as A:B:C:D. A and D are known as extreme terms, while B and C are known as middle terms.

Extramarks’ Revision Notes for Class 6 Mathematics Chapter 12 Ratio and Proportion are available on  the website. Students can access them at their leisure and prepare well for their Class 6 examination. Subject matter experts prepare these Class 6 Mathematics Notes in a simple and easy format.

### Access Class 6 Mathematics Chapter 12 – Ratio and Proportion Notes

Comparison by Difference

• When comparing quantities of the same type, the differences between them are usually taken.
• A comparison done by division is sometimes preferable to a comparison based on their differences.
• When the two quantities are compared in terms of ‘how many times,’ this comparison is called ‘ratio’.

Comparison by Division

• In many cases, division is used to make a more meaningful comparison of amounts, such as determining how many times one quantity is to the other.
• This procedure is known as comparison by ratio.
• A ratio is represented by a colon ‘:’.
• The two quantities to be compared must be measured by the same unit. If they are not in the same unit, they should be converted into the same units before calculating the ratio.
• To obtain equivalent ratios, multiply or divide the numerator and denominator by the same number.
• Different scenarios can result in the same ratio.
• It is important to remember that the ratio a : b is different from the ratio b : a. As a result, it is crucial to consider the order of the quantities when expressing a ratio.
• For instance, the 3 : 5 ratio and the 5 : 3 ratio are not equivalent.
• A ratio can be written as a fraction, such as 7 : 9, which is written as 79.
• A ratio can be expressed in the most basic form.
• For instance, the ratio 78: 39 is referred to as 78/39.
• A ratio can be expressed in the simplest form as 78/39=2/1.
• Consequently, the ratio of 78 to 39 has the lowest form of 2 to 1.
• Two ratios are comparable if their corresponding fractions are the same.
• Two ratios are in proportion when they are equal. The symbols “::” or “=” are used to indicate that two ratios are in proportion.
• If two ratios are not equal, they are not in proportion.
• When the four quantities in a statement of proportion are listed in the correct order, they are referred to as the respective terms.
• The first and fourth terms are extreme terms. The second and third terms are known as the middle terms.
• The unitary method involves finding the value of one unit first, then finding the value of the necessary quantity of units.

### 1. What do you understand by ratio?

A ratio is a comparison of quantities. For example, when we have two quantities of the same type, we compare them to see which is greater. Ratios are used to describe such comparisons. Chapter 12 of Class 6 Mathematics is an important chapter as students learn more about ratio and how to compare quantities using various methods. The chapter is interesting and simple to learn if the numericals are practised on a regular basis.

### 2. Explain comparison by difference.

The comparison by difference is where the differences between two quantities are calculated and then compared. However, it is not always preferred. For example, to compare the numbers 3 and 9, the differences may be calculated by subtracting the smaller number from the greater number, i.e., 9 – 3 = 6. The number 6 forms the basis for such a comparison and indicates how much  9 is greater than 3.

### 3. Explain comparison by division method.

The comparison by division method uses ratios to compare two quantities. The symbol used to indicate a ratio is (:). To compare two numbers using ratio, the two quantities must be in the same unit. If the quantities are not in the same unit, they must be converted to similar units before they can be compared using this method. When the numerator and denominator are multiplied by the same number, it results in an equivalent ratio.

### 4. What is a unitary method?

A unitary method involves determining the value of one unit and then calculating the value of the required units.

For example, let us calculate the cost of 20 pens. First, we look at the price of a pen. For example, if the cost of one pen is Rs 5, it is simple to calculate the cost of twenty pens.

20 x 5 = 100. Therefore, the cost of 20 pens is Rs. 100 as per the unitary method.

### 5. How can students effectively learn the concepts in Class 6 Mathematics of Chapter 12?

The first step is to develop a clear understanding of the topics discussed in the chapter. Regular revisions and consistent practice of the chapter’s theorems, equations, and problems will keep the concepts fresh in the students’ minds. Moreover, their ability to solve questions will increase as a result of their strong conceptual foundation.

### 6. What is proportion?

Two ratios are said to be in proportion when they are equal to one another. As a result, there are proportionally four different entities involved. Proportionality is indicated by the symbols “::” or “=”.