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Tenths and Hundredths - Measurement of Length and Money in Decimals

Grade 5CBSE

Review the key concepts, formulae, and examples before starting your quiz.

🔑Concepts

Tenths represent one part out of ten equal divisions of a whole. In decimal notation, one-tenth is written as 0.10.1. Visually, imagine a 1 cm1 \text{ cm} segment on a ruler divided into 1010 equal small divisions; each division represents 1 mm1 \text{ mm} or 0.1 cm0.1 \text{ cm}.

Hundredths represent one part out of a hundred equal divisions of a whole, written as 0.010.01. Visually, if you look at a square grid consisting of 100100 small squares, shading exactly one square represents 0.010.01 (one-hundredth) of the entire grid.

When measuring length, we often use the relationship between millimeters and centimeters. Since 10 mm=1 cm10 \text{ mm} = 1 \text{ cm}, a single millimeter is 110\frac{1}{10} of a centimeter. Therefore, a measurement like 3 mm3 \text{ mm} is written as 0.3 cm0.3 \text{ cm}.

For larger length measurements, we convert centimeters to meters. Because 100 cm=1 m100 \text{ cm} = 1 \text{ m}, 1 cm1 \text{ cm} is 1100\frac{1}{100} of a meter, written as 0.01 m0.01 \text{ m}. Visually, if a ribbon is 150 cm150 \text{ cm} long, it is 11 whole meter and 5050 hundredths of a meter, or 1.50 m1.50 \text{ m}.

Money in India is calculated using Rupees and Paise. Since 100 Paise=1100 \text{ Paise} = ₹ 1, one Paisa is one-hundredth of a Rupee. We use a decimal point to separate Rupees from Paise; for example, 75 Paise75 \text{ Paise} is written as 0.75₹ 0.75.

The Decimal Place Value Chart helps organize these parts. The first position to the right of the decimal point is the 'Tenths' place, and the second position to the right is the 'Hundredths' place. For example, in 4.564.56, 55 is the number of tenths and 66 is the number of hundredths.

📐Formulae

1 mm=110 cm=0.1 cm1 \text{ mm} = \frac{1}{10} \text{ cm} = 0.1 \text{ cm}

1 cm=1100 m=0.01 m1 \text{ cm} = \frac{1}{100} \text{ m} = 0.01 \text{ m}

1 Paisa=1100=0.011 \text{ Paisa} = ₹ \frac{1}{100} = ₹ 0.01

Total Centimeters=Whole Centimeters+Millimeters10\text{Total Centimeters} = \text{Whole Centimeters} + \frac{\text{Millimeters}}{10}

Total Rupees=Whole Rupees+Paise100\text{Total Rupees} = \text{Whole Rupees} + \frac{\text{Paise}}{100}

💡Examples

Problem 1:

The length of a pencil is 14 cm14 \text{ cm} and 8 mm8 \text{ mm}. Express this length in centimeters using decimals.

Solution:

Step 1: Identify the relationship between mm and cm. 1 mm=0.1 cm1 \text{ mm} = 0.1 \text{ cm}. \nStep 2: Convert 8 mm8 \text{ mm} to cm. 8×0.1=0.8 cm8 \times 0.1 = 0.8 \text{ cm}. \nStep 3: Add the converted mm to the whole cm. 14 cm+0.8 cm=14.8 cm14 \text{ cm} + 0.8 \text{ cm} = 14.8 \text{ cm}.

Explanation:

We convert the millimeter part into tenths of a centimeter and combine it with the whole centimeters using a decimal point.

Problem 2:

Convert 77 Rupees and 55 Paise into decimal form using the ₹ symbol.

Solution:

Step 1: Recall that 100 Paise=1100 \text{ Paise} = ₹ 1, so 1 Paisa=0.011 \text{ Paisa} = ₹ 0.01. \nStep 2: Convert 5 Paise5 \text{ Paise} to Rupees. 5 Paise=5100=0.055 \text{ Paise} = ₹ \frac{5}{100} = ₹ 0.05. \nStep 3: Add the whole Rupees to the decimal part. 7+0.05=7.05₹ 7 + ₹ 0.05 = ₹ 7.05.

Explanation:

Since 55 Paise is less than 1010, it represents 55 hundredths. We must place a 00 in the tenths place to correctly show 55 hundredths as 0.050.05.