91Ó°ÊÓ

Understanding decimal place value is essential when working with numbers that are not whole, such as money, measurements, and scientific data. The decimal point is a critical component as it separates the whole number part from the fractional part of a decimal number. Each position to the right of the decimal point indicates a fractional part of a base 10 number system, where each place is ten times smaller than the place to its left.

Let's break it down with an example. If we take the number 21.45, '21' is the whole number part showing us how many whole items we have, while '.45' is the decimal part indicating a part of a whole. To express this decimal in words correctly, it's important to identify and articulate each place value accurately.

The first digit to the right of the decimal point is known as the 'tenths place'. This place tells us how many tenths are present in our decimal number. Imagine cutting a whole item into ten equal parts; one part of this is a tenth. In the decimal 21.45, the number 4 is in the tenths place, meaning there are four tenths.

Therefore, when writing decimals in words, we would start by saying the whole number, followed by the value in the tenths place. For instance, '21.45' would begin with 'twenty-one and four tenths’… but since there's more to the decimal, we keep going to include the hundredths place.

Continuing to the second digit to the right of the decimal point, we encounter the 'hundredths place'. This signifies how many hundredths are in the decimal. If a whole is split into 100 equal pieces, one piece would represent one hundredth. For our example number 21.45, the 5 occupies the hundredths place and denotes that there are five hundredths.

To fully express '21.45' in words, we combine the value of the tenths and the hundredths place: 'forty-five hundredths'. Hence, '21.45' in words is 'twenty-one and forty-five hundredths'. Noting the hundredths place is vital because it provides the precision often required in financial transactions, scientific measurements, and other detailed calculations.