Class 7 Maths - ICSE
Decimal Fractions
The chapter 'Decimal Fractions' in Class 7 ICSE Mathematics builds upon your foundational knowledge of fractions and decimals from lower grades. You will learn advanced arithmetic operations including multiplication and division of decimals by powers of 10, as well as by other decimals. The chapter covers converting between fractions and decimals, expressing metric units in decimal form, and solving practical word problems. Mastering decimals is crucial for board exams because it forms the computational backbone for percentages, ratio and proportion, and commercial mathematics chapters in higher classes, frequently appearing in both objective and subjective sections.
Start Learning FreeKey Concepts
Multiplication of Decimals
To multiply two decimals, first multiply them as whole numbers, then place the decimal point in the product so that the number of decimal places equals the sum of the decimal places in the multipliers.
Division by Powers of 10
When dividing a decimal number by 10, 100, or 1000, shift the decimal point to the left by as many places as there are zeros in the divisor.
Division of a Decimal by Another Decimal
To divide by a decimal, convert the divisor into a whole number by multiplying both the dividend and divisor by the same power of 10, then perform normal long division.
Recurring and Terminating Decimals
A terminating decimal has a finite number of digits after the decimal point, while a recurring (repeating) decimal has a digit or block of digits that repeats endlessly.
Conversion of Units
Decimals are extensively used to convert smaller metric units to larger ones, such as converting centimeters to meters or grams to kilograms using place value.
Important Formulas
Board Exam Info
In ICSE Class 7 Mathematics examinations, this chapter typically carries around 6 to 8 marks. Questions usually include direct simplification of decimal expressions, conversion problems, and 2-mark or 3-mark word problems involving money, length, and mass.
Frequently Asked Questions
How do I know which direction to move the decimal point when multiplying or dividing by 10, 100, etc.?
Remember the trick: Multiplication makes numbers bigger, so move the decimal point to the right. Division makes numbers smaller, so move it to the left.
What should I do if the divisor has a decimal point during division?
Always shift the decimal point of the divisor to the right until it becomes a whole number, and remember to shift the decimal point of the dividend by the exact same number of places.
How many decimal places should I write in my final answer for recurring decimals?
Usually, questions will specify rounding off to two or three decimal places, or you can use the bar notation (e.g., 0.33...) to show repetition.
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