CBSE Class 5 Mathematics NCERT Solutions: Tenths and Hundredths

NCERT Solutions PDF Class 5 PDF

CBSE Class 5 Mathematics chapter Tenths and Hundredths introduces the basics of decimal numbers. The NCERT Solutions help students understand concepts like tenths and hundredths through clear explanations and problem-solving. You'll learn how to work with measurements in centimeters and millimeters, convert between them, and represent fractions as decimals. For example, you'll see how 0.9 cm means nine-tenths of a centimeter. The chapter also covers comparing decimal numbers and applying these ideas to practical situations, like figuring out how many frogs fit on a finger or using a meter scale. These solutions aim to build a solid understanding of decimal arithmetic, which is important for future math topics and exams.

Quick info

BoardCBSE
ClassClass 5
SubjectMathematics
Session2026
LanguageEnglish
TypeNCERT Solutions
Chapter10 Tenths And Hundredths

Chapter summary

Chapter 10, "Tenths and Hundredths," for Class 5 Mathematics NCERT Solutions, focuses on introducing and applying the concepts of decimal numbers. It covers measuring lengths using scales, converting between millimeters and centimeters, and understanding decimal notation. The exercises involve practical applications like estimating sizes and quantities based on decimal measurements, reinforcing the relationship between fractions (tenths) and decimals. These solutions offer a clear path to mastering basic decimal operations and measurement conversions.

Learning outcomes

  • Understand the concept of tenths and hundredths in decimal numbers.
  • Measure lengths accurately in centimeters and millimeters.
  • Convert measurements between centimeters and millimeters.
  • Represent decimal numbers in words and figures.
  • Apply decimal concepts to solve practical measurement problems.
  • Relate decimal fractions to their fractional equivalents (e.g., 0.9 cm as nine-tenths of a cm).

Topics covered

Paper topics

  • Introduction to Tenths
  • Introduction to Hundredths
  • Decimal Representation of Lengths
  • Measurement in Centimeters (cm)
  • Measurement in Millimeters (mm)
  • Conversion between cm and mm
  • Understanding Decimal Fractions
  • Comparing Decimal Numbers
  • Estimating Quantities using Decimals
  • Word Problems involving Decimals

Important topics

  • Understanding and representing tenths and hundredths
  • Converting between cm and mm
  • Reading and writing decimal numbers
  • Solving measurement-based word problems
  • Relating decimals to fractions

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Questions and Solutions

Question 1

What was the length of the smallest pencil you have used?
Solution:

The length of the smallest pencil used can vary from person to person. Based on common experience, a small pencil might be around 5 cm long. This is a personal observation question, and the answer reflects a typical small pencil size.

Question 2

How long is this pencil? Guess ---cm. Measure it using a scale. How good is your guess?
Solution:

This question requires a physical measurement. First, you would guess the length of a given pencil. For example, one might guess it to be 3.5 cm. Then, using a ruler or scale, you would measure the actual length. If the actual measurement is, for instance, 3.6 cm, then the guess was quite good as it was very close to the actual length.

Question 3

What is the length of this pencil? ——— mm. What is its length in centimetre?
Solution:

To answer this, you need to measure the pencil using a ruler that shows millimeters. Let's assume the pencil measures 6 mm. To convert millimeters to centimeters, we use the relationship that 10 mm = 1 cm. Therefore, 6 mm is equal to \frac{6}{10} cm, which is 0.6 cm. So, the length of the pencil is 6 mm, or 0.6 cm.

Question 4

Have you seen frogs? Where? How many different types of frogs have you seen? Are all the frogs of the same length? Here are two interesting examples.
Solution:

This is a question that encourages observation and personal experience. Yes, one might have seen frogs in gardens, near ponds, or in wet areas. Different types of frogs exist, varying in color and size. For example, some frogs are small and green, while others can be larger and brown. It is evident that frogs are not all the same length; there is a wide variation in their sizes.

Question 5

This kind of frog is among the smallest in the world. Its length is only 0.9 cm! >- Guess how many such frogs can sit on your little finger!
Solution:

The length of this small frog is given as 0.9 cm. A typical adult little finger is about 5 to 7 cm long. If we consider a little finger to be approximately 5 cm long, we can estimate how many 0.9 cm frogs would fit. Dividing the finger length by the frog's length: 5 \text{ cm} \div 0.9 \text{ cm/frog} \approx 5.5 \text{ frogs}. Therefore, about 5 or 6 such frogs could potentially sit on a little finger, depending on the finger's exact size and how closely they sit.

Question 6

But this is among the biggest frogs. It is as long as 30.5 cm.
Solution:

This statement provides information about the size of a bullfrog, which is one of the largest frog species. Its length is given as 30.5 cm. This highlights the significant difference in size between the smallest frogs (like the 0.9 cm one) and the largest ones.

Question 7

What does 0.9 cm mean? It is the same as—— millimetres. We can also say this is nine- tenths of a cm. Right?
Solution:

The decimal number 0.9 cm means 9 tenths of a centimeter. Since 1 centimeter is equal to 10 millimeters, 9 tenths of a centimeter is equivalent to 9 millimeters. So, 0.9 cm is indeed the same as 9 mm, and it is correctly stated as nine-tenths of a cm.

Question 8

So 30.5 cm is the same as——-cm and——— millimetres.
Solution:

The number 30.5 cm can be broken down into its whole number part and its decimal part. The whole number part is 30 cm. The decimal part is 0.5 cm. Since 1 cm is equal to 10 mm, 0.5 cm is equal to 0.5 \times 10 = 5 millimeters. Therefore, 30.5 cm is the same as 30 cm and 5 millimeters.

Question 9

About how many of the big frogs will fit on the 1 m scale?
Solution:

We know that the length of a big frog (bull frog) is 30.5 cm. A 1-meter scale is equal to 100 centimeters. To find out how many big frogs can fit on a 1-meter scale, we divide the total length of the scale by the length of one frog: \frac{100 \text{ cm}}{30.5 \text{ cm/frog}} \approx 3.27 \text{ frogs}. Since we can only fit whole frogs, approximately 3 big frogs can fit along a 1-meter scale. There might be some space left over.

Question 10

If they sit in a straight line about how many of the small frogs will cover 1 m?
Solution:

The length of a small frog is 0.9 cm, which is equal to 9 mm. A 1-meter scale is equal to 100 cm, or 1000 mm. To find out how many small frogs will cover 1 meter, we divide the total length of the scale in millimeters by the length of one small frog in millimeters: \frac{1000 \text{ mm}}{9 \text{ mm/frog}} \approx 111.11 \text{ frogs}. Therefore, about 111 small frogs can cover a length of 1 meter when placed in a straight line.

Question 11

Length of the nail – 2 cm and.....mm or 2. – cm.
Solution:

To determine the length of the nail, we need to observe the provided image or scale. Assuming the nail measures 2 cm and 9 mm, we can convert this to centimeters. Since 9 mm is equal to \frac{9}{10} cm or 0.9 cm, the total length of the nail is 2 cm + 0.9 cm = 2.9 cm. So, the length is 2 cm and 9 mm, or 2.9 cm.

Question 12

The length of this lady's finger (bhindi) is 8 cm and 3 mm. We can also write it as 8.3 cm.
Solution:

This statement provides an example of how to write a measurement in two different ways. The length of the lady's finger is given as 8 cm and 3 mm. To write this in centimeters only, we convert the millimeters part to centimeters. Since 3 mm is equal to \frac{3}{10} cm or 0.3 cm, the total length is 8 cm + 0.3 cm = 8.3 cm. This demonstrates the conversion from a mixed unit measurement to a decimal centimeter measurement.

Common mistakes

  • Incorrectly converting between centimeters and millimeters.
  • Misinterpreting decimal notation (e.g., confusing 0.9 with 9.0).
  • Errors in estimating or calculating quantities based on decimal measurements.
  • Difficulty in relating decimal fractions to their fractional forms.

Revision tips

  • Practice converting lengths between cm and mm repeatedly.
  • Visualize decimal numbers by relating them to physical objects and measurements.
  • Work through the word problems to understand the practical application of decimals.
  • Pay close attention to the place value of digits in decimal numbers.
  • Use a ruler to measure various objects and write their lengths in both cm and mm, and as decimals.

Practice MCQs

Q1. What is the length of 0.9 cm in millimeters?

Q2. A pencil is measured to be 6 mm long. What is its length in centimeters?

Q3. The length of a bull frog is 30.5 cm. How many centimeters and millimeters is this?

Q4. Which of the following represents 'nine-tenths of a cm'?

Q5. If a nail is 2 cm and 9 mm long, what is its length in centimeters?

Frequently asked questions

What is the main focus of the Class 5 Maths Chapter 10: Tenths and Hundredths?

This chapter focuses on introducing students to decimal numbers, specifically tenths and hundredths, and their application in measuring lengths, converting units (cm to mm), and solving related word problems.

How do these NCERT Solutions help students?

These solutions provide clear, step-by-step explanations for each problem, helping students understand the concepts of decimals and measurements, and how to solve them accurately for their exams.

What is the relationship between centimeters and millimeters explained in this chapter?

The chapter explains that 1 centimeter is equal to 10 millimeters, and demonstrates how to convert between these units using decimal notation (e.g., 0.9 cm = 9 mm).

Can students learn to measure accurately using these solutions?

Yes, the solutions involve practical measurement exercises, encouraging students to use scales and understand how to represent lengths in both centimeters and millimeters, and as decimal values.

How are decimal numbers represented in this chapter?

Decimal numbers are represented in various ways, including as measurements (e.g., 30.5 cm), as fractions of a whole (e.g., 0.9 cm is nine-tenths of a cm), and through conversion between units.

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