03 - Numbers and arithmetic.ipynb

Kernel: Python 3 (system-wide)

Exercise 3.1

In your head, or on paper, work out the following arithmetic as you would expect Python to do it using the rules of precedence.

• 5 * 5 - 5 = ?

• 10 - 2 * 3 = ?

• 20 + 5 * 2 - 10 = ?

• 4 + 4 / 2 = ?

• 2 * 5 ** 2 = ?

• 9 / 3 ** 2 = ?

Check your answers by typing them into the code cell below.

print(5 * 5 - 5)
print(10 - 2 * 3)
print(20 + 5 * 2)
print(4 + 4 / 2)
print(2 * 5 ** 2)
print(9 / 3 ** 2)

Exercise 3.2

What are the types of each of the following numbers?

• -6

• 10.3

• 99.0

• -1.0

Check your answers in the code cell below.

print( type(-6) )
print( type(10.3) )
print( type(99.0) )
print( type(-1.0) )

Exercise 3.3

1. What type of number do you get if you do 4 / 2?

2. What type of number do you get if you do 4 // 2?

Check your answer below.

print( type(4/2) )
print( type(4//2) )

Exercise 3.4

Round the following floats to the given number of decimal places.

• 34.2694 to 2dp

• -1.4 to 0dp

• 1024.234 to 1dp

print( round(34.2694, 2) )
print( round(-1.4, 0))
print( round(1024.234, 1) )

Exercise 3.5

What are the circumference and area of a circle of radius 5.4 cm rounded to 1 decimal place?

If you've forgotten what the circumference and area of a circle are use google.

# Circumference is 2 * pi * radius
print( round(2 * 3.142 * 5.4, 1) )

# Area is pi * radius**2
print( round(3.142 * 5.4**2, 1) )

Exercise 3.6

In the code cell below calculate the average of the following set of numbers to 2dp:

11, 11, 13.5, 7.5, 13.5, 22.5

print( round( (11 + 11 + 13.5 + 7.5 + 13.5 + 22.5)/6, 2 ) )

Exercise 3.7

Using Python code calculate what 321 minutes is in hours and minutes? (E.g., 61 minutes is 1 hour and 1 minute.)

Find the remainder of the following:

• $\frac{59}{2}$

• $\frac{100}{2}$

print( 321 // 60 )
print( 321 % 60)
print( 59 % 2 )
print( 100 % 2 )