Decimals (Math 3)

Decimals (Math 3)

Chapter 10 (pages 88-97)

Understanding tenths

The diagram is divided into 10 equal parts.

Each part is one tenth. It is also 1/10 on the number line.

We can see that 10 tenths make 1 whole.

The fraction 1/10 can be written as a decimal.

A decimal has a whole number part and a fraction part that is separated by a decimal point.

We can draw a tenths column in a place value table.

The decimal 0.1 has 0 ones and 1 tenth.

Look at the diagram. What decimal does the shaded part represent?

3 tenths or 3/10 of the diagram is shaded. 3/10 = 0.3

Let us now look at the decimal 0.3 in a place value table.

In the decimal 0.3,

(a) the digit 0 is in the ones place. It stands for 0 ones and has a value of 0.

(b) the digit 3 is in the tenths place. It stands for 3 tenths and has a value 0.3

Look at the diagram. Write 10/10 as a decimal.

10 tenths = 1 one

So, 10/10 = 1.

Write 15 tenths as a decimal.

We regroup 15 tenths into ones and tenths.

15 tenths = 1 one 5 tenths = 1.5

Write 3 ones and 4 tenths as a decimal.

(page 91)

Understanding hundredths

The diagram is divided into 100 equal parts.

Each part is one hundredth or 1/100 of the whole.

We can use a number line to show 1/100.

First, we divide the interval from 0 to 1 on a number line into tenths.

Each tenth is further divided into 10 equal parts.

The fraction 1/100 can also be written as a decimal.

1/100 (1 hundredth) = 0.01

Look at the diagram. What decimal does the shaded part represent?

3 hundredths or 3/100 of the diagram is shaded.

3/100 = 0.03