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Measurement - Conversion of Units

Grade 4ICSE

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

🔑Concepts

Introduction to Metric Units: In the metric system, we use standard units to measure length, mass, and capacity. The meter (mm) is the base unit for length, the gram (gg) for mass, and the liter (LL) for capacity. Think of these as the 'home' units from which all other units are derived.

The Metric Staircase Visual: Imagine a staircase where each step represents a unit. From top to bottom, the steps are Kilo (kk), Hecto (hh), Deca (dada), Base Unit (m,g,Lm, g, L), Deci (dd), Centi (cc), and Milli (mm). Every step you move down, you multiply the value by 1010, and every step you move up, you divide the value by 1010.

Converting Larger Units to Smaller Units: When you convert a larger unit to a smaller unit (like kmkm to mm), the number gets bigger. You should multiply the value by the conversion factor. For example, since 1 km1 \text{ km} is larger than 1 m1 \text{ m}, you multiply by 10001000.

Converting Smaller Units to Larger Units: When you convert a smaller unit to a larger unit (like mLmL to LL), the number gets smaller. You should divide the value by the conversion factor. For example, to change 5000 mL5000 \text{ mL} into liters, you divide by 10001000.

Units of Length: Length measures how long or wide an object is. Visualize a ruler: 1 cm1 \text{ cm} is divided into 1010 small millimeters (mmmm). A meter rod consists of 100 cm100 \text{ cm}, and a long road distance is measured in kilometers (kmkm), where 1 km1 \text{ km} equals 10001000 meters.

Units of Mass (Weight): Mass measures how heavy an object is. A small paperclip weighs about 1 g1 \text{ g}, while a heavy bag of rice might weigh 1 kg1 \text{ kg}. To convert kilograms to grams, we use the factor of 10001000.

Units of Capacity: Capacity measures the amount of liquid a container can hold. A small medicine spoon holds about 5 mL5 \text{ mL}, whereas a large bottle of water might hold 1 L1 \text{ L}. The relationship is always 1 L=1000 mL1 \text{ L} = 1000 \text{ mL}.

Decimal Point Movement: Converting by 10,100, or 100010, 100, \text{ or } 1000 is like shifting a decimal point. Multiplying moves the decimal to the right (making the number larger), and dividing moves it to the left (making the number smaller).

📐Formulae

1 km=1000 m1 \text{ km} = 1000 \text{ m}

1 m=100 cm1 \text{ m} = 100 \text{ cm}

1 cm=10 mm1 \text{ cm} = 10 \text{ mm}

1 kg=1000 g1 \text{ kg} = 1000 \text{ g}

1 g=1000 mg1 \text{ g} = 1000 \text{ mg}

1 L=1000 mL1 \text{ L} = 1000 \text{ mL}

Value in smaller unit=Value in larger unit×Conversion Factor\text{Value in smaller unit} = \text{Value in larger unit} \times \text{Conversion Factor}

Value in larger unit=Value in smaller unit÷Conversion Factor\text{Value in larger unit} = \text{Value in smaller unit} \div \text{Conversion Factor}

💡Examples

Problem 1:

Convert 8 kg 450 g8 \text{ kg } 450 \text{ g} into grams.

Solution:

8 kg=8×1000 g=8000 g8 \text{ kg} = 8 \times 1000 \text{ g} = 8000 \text{ g} 8000 g+450 g=8450 g8000 \text{ g} + 450 \text{ g} = 8450 \text{ g}

Explanation:

To convert a mixed unit into a single smaller unit, first convert the larger part (kgkg) into the smaller unit (gg) by multiplying by 10001000. Then, add the remaining grams to get the total.

Problem 2:

Convert 700 cm700 \text{ cm} into meters.

Solution:

700÷100=7 m700 \div 100 = 7 \text{ m}

Explanation:

Since we are converting from a smaller unit (cmcm) to a larger unit (mm), we divide by the conversion factor. Because 100 cm=1 m100 \text{ cm} = 1 \text{ m}, we divide 700700 by 100100 to get 77.