Page 97 - ICSE Math 5

Decimals
7 Decimals

Learning Outcomes

Students will be able to learn:
 the relationship between fractions and decimal fractions.
 to find the place value of decimal numbers.
 to write expanded form of decimal numbers.
 types of decimal numbers—equivalent, like and unlike decimals.
 to compare decimal numbers.
 to add and subtract decimal numbers.
 to solve word problems on addition and subtraction of decimals.
 to multiply decimal numbers by 10, 100 and 1,000.
 to multiply a decimal number by a whole number and a decimal number by another decimal number.

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We already know that a fraction is a part of a whole. For example, and represent fractions.
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The fractions which have 10, 100, 1,000, and so on as their denominator are called decimal
fractions. These fractions can also be written in the form of decimals (decimal numbers).
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For example, and can be written as 0.5 and 3.4 in decimal form. The point or dot in
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between the two digits is called the decimal point.
Let’s learn more about decimal numbers.

A decimal number has two parts. The part before the decimal point is called the whole number
or integral part and the part after the decimal point is called the decimal part or fractional part. A
decimal number can be written with a whole number to show a complete whole and a fractional
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part. For example, to express 4 complete wholes and 10 fractional part, we can write 4.5 in the
decimal form.

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4 and = 4.5
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Place Value of Decimal Numbers

We know that when we move towards the left in a place value chart, the value of a digit increases
by ten times for each place. The value of a digit also changes on moving towards the right in a
place value chart. As we keep moving to the right, the value of a digit decreases every time and
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gets ten times smaller, i.e., it decreases by for each place.
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