__Objective__

At the end of this lesson, students should know and understand the place value and value of decimal numbers.

__Decimal Vocabulary__

**Decimal/Decimal Number**: Is a number that represents a whole number and parts of a whole by separating them with a point.**Decimal point**: Is a point separating the ones and tenths in a decimal number.**Ones**: Is the place value of the digit on the immediate left hand side of the decimal point.

**Tenth**: Is the first number on the immediate right hand side of the decimal point. It is the first decimal place and represents parts out of 10 equal parts (E.g. “**.**8” means 8 parts out of 10. i.e.).**Hundredth**: Is the second number on the right hand side of the decimal point. It is the second decimal place and represents parts out of 100 equal parts (E.g.“**.**05” means 5 parts out of 100 i.e ).**Thousandth**– Is the third number on the right hand side of the decimal point. It is the third decimal place and represents parts out of 1000 equal parts (E.g.“**.**009” means 9 parts out of 1000 i.e.).**Decimal Place**: Is the number of digits after the decimal point.

The decimal point separates the whole number from the fraction part of a decimal number. In the above diagram, the whole number is 342,368. The

lowest place value of whole numbers is the units. Therefore, from right to left **on the left hand side of the decimal point**: **units, tens, hundreds, thousands, ten thousands and hundred thousands.**

**On the right hand side of the decimal point**, the highest place value of the fraction part begins: **tenth, hundredth, thousandth, etc.** as shown in the illustration above.

__Example 1__

**Write the value and place value of the underlined digits in the following decimal numbers**.

a) 24**8**6.08 b) 35276.**8**26

c)** 3**59,901.620 d) 24.24**1**

e) 19.4**2**11 f) 78 **9**.1515

__Solution__

__Example 2__

**What is the total value of the underlined figures in each of these?**

a) **2**4.**5** b) 8**28**.84

__Solution__

a) **2**4.**5** = 2 tens and 5 tenths

= 20 + 0.5

= **20.5**

b) 8**28**.84 = 2 tens and 8 units

= 20 + 8

=** 28**

**An Abacus or Notation Board can be used to illustrate decimals based on the knowledge of place value. Let’s look at the Abacus below.**

**Notation boards work in the same way as the Abacus. Below are some illustrations on Notation boards.**

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