Your phone is full of data

Look at your phone. It shows the time. It shows your battery. It shows your name.

Some of it is a number. Some of it is words. Some of it is a yes or no.

A program must know which is which. The kind of value is called its data type. A data type is the kind of thing a value is.

Key words

Word	What it means	Example
Data type	The kind of thing a value is.	integer, float, string, Boolean
Integer	A whole number with no decimal point.	42
Float	A number with a decimal point.	2.50
String	Text. It goes inside quote marks.	"hello"
Boolean	Only two values: True or False.	True
Variable	A name that holds a value.	goals = 3
Decimal point	The dot in a number like 2.50.	2.50

The cells students fill in are left blank in this preview.

Whole numbers: integers

An integer is a whole number. It has no decimal point.

Use an integer to count things. Your team scored 3 goals. The bus has 40 seats. You cannot score 2.5 goals, so goals are integers.

Try it: an integer

Code: python

goals = 3
print(goals)
print(type(goals))

# Change 3 to 5 and press Run again.

Numbers with a point: floats

A float is a number with a decimal point.

Use a float for money, height and weight. A bus ticket costs 2.50. Your height is 1.75 metres. Both are floats.

Try it: a float

Code: python

fare = 2.5
print(fare)
print(type(fare))
print(fare * 2)

Use a dot

data-callouts.tip.label

Python uses a dot, not a comma. Write 2.5, not 2,5. Python also prints 5.0 for two tickets. That is still a float.