58 NUMBERS •^ DECIMAL NUMBERS

Decimals are fractions, too!

The digits after the point in a decimal number are just another way of

showing fractions, or numbers less than one. Let’s find out how they work.

Hundredths

Now let’s do the same with 2^72 ⁄ 100.

When we put all the digits into their

place-value columns, we can see that

2 72 ⁄ 100 is the same as 2.72.

Tenths

If we put 2^7 ⁄ 10 into place-value columns,

the whole number 2 goes in the ones column

and the 7 in the tenths column to stand for

(^7) ⁄ 10. So we can also write 2 (^7) ⁄ 10 as 2.7.
.
O
2 7
.
O
2 7 2
7
210 =
72
(^2100)
.
O
2 7 2
721
(^21000)
Thousandths
Finally, when we put 2^721 ⁄ 1000
into place-value columns, we see that
2 721 ⁄ 1000 is the same as 2.721.
1

=
The 7 in the
tenths column
stands for^7 ⁄ 10
This 2
stands
for^2 ⁄ 100
This 1 stands
for^1 ⁄ 1000
10

Decimal numbers

Decimal numbers are made up of whole numbers and fractions of numbers.

A dot, called a decimal point, separates the two parts of a decimal number.

Decimals are really useful when we want

to make accurate measurements, such as

recording the runners’ times in this race.

On the scoreboard, the digits to the left of the

decimal point show whole seconds. The digits

to the right show parts, or fractions, of a second.

1

10

1

1001

10

1

100

1

1000

1

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