Introduction to Decimals

What are decimals?

Decimals are another way to write parts of a whole — just like fractions, but using a decimal point.

Fraction	Decimal	We say
1/10	0.1	”zero point one” or “one tenth”
3/10	0.3	”zero point three” or “three tenths”
1/100	0.01	”zero point zero one” or “one hundredth”
25/100	0.25	”zero point two five” or “twenty-five hundredths”

The decimal point separates whole numbers from parts:

Tens	Ones	.	Tenths	Hundredths
1	4	.	7	3

14.73 = 10 + 4 + 7/10 + 3/100 = 10 + 4 + 0.7 + 0.03

Each place to the right of the decimal is 10 times smaller:

In 14.73, the 1 is in the tens place (10) and the 4 is in the ones place (4).

The 7 is in the tenths place — it means 7/10 or 0.7.

The 3 is in the hundredths place — it means 3/100 or 0.03.

14.73 = 10 + 4 + 0.7 + 0.03. Each place is 10 times smaller as you move right.

1 / 4

0.25

25/100 = 1/4

Value 0.25

Key idea: To convert a fraction to a decimal, divide the numerator by the denominator.

$3.45 means 3 whole dollars and 45 cents, which is also 3 dollars, 4 tenths of a dollar, and 5 hundredths of a dollar.

You’ve been using decimals every time you handle money!

What decimal is the same as 7/10?

In the number 5.82, what does the 8 represent?

Write 3/4 as a decimal.

Which fraction equals 0.25?

Write 0.4 as a fraction with denominator 10. Just enter the numerator.

You have $2.35. How many cents is that in total?

cents

Quick-Fire Round

Score: 0 / 6 Problem 1 of 6