# Week 2: Exercise Solutions

## Exercise 2.1

- Using
`2**100`

we find that there are 31 digits in 2^{100}.
- Using
`3**11 % 11`

we find the answer 3.

## Exercise 2.2

- A float has a decimal point in it:
`3.0`

represents a float and `3`

represents an integer.
- It forgets the fractional part, so
`int(-7.8)`

is `-7`

.

## Exercise 2.3

# To calculate body mass index
height = float(input("What is your height in metres? "))
weight = float(input("What is your weight in kilos? "))
print("Your BMI is", weight / height**2)

## Exercise 2.4

# To decide if a number is non-zero
number = int(input("Enter an integer: "))
print("It is", number != 0, "that your number is non-zero")

## Exercise 2.5

In the first case, the condition is always true so the program will just print

over and over again forever and will never print `Lobster thermidor`

.

In the second case the condition is never true, so will not print anything about spam but will only print `Lobster thermidor`

.