Introduction to Python: Unit Exam B
Printing and joining strings, arithmetic, casting with int(), float() and str(), comparisons and if statements, and a program to write.
Instructions
- Time allowed
- 25 minutes
- Total marks
- 25
- Calculator
- No calculator is permitted.
- Answer all the questions.
- The number of marks for each question is shown in brackets. Use it as a guide to how much to write.
- The clock at the top counts down from the real time allowed. When it reaches zero the paper is locked and marked, as it would be collected in the exam hall.
- Read every question to the end before answering. Where a question says tick two boxes, tick exactly two: ticking more than asked scores nothing. Type one word and number answers carefully, because they are marked exactly.
Questions
Answer every question, then finish the paper to have it marked. Marking as you go teaches you far less.
Tick one box.
- LD Shows output on the screen
print() displays output.
a = 4
b = 6
print(a * b)- L24
4 x 6 = 24.
first = "Sam"
print("Hi " + first + "!")- LHi Sam!
The strings are joined: Hi, then Sam, then !, giving Hi Sam!
print((2 + 3) * 4)- L20
Brackets first: 2 + 3 = 5, then 5 x 4 = 20.
| int() | float() | str() | |
|---|---|---|---|
| Turn "12" into a whole number | |||
| Turn 7 into "7" so it can be joined to some text | |||
| Turn "2.5" into a decimal number |
Tick one box in each row.
- LTurn "12" into a whole number: int()
- LTurn 7 into "7" so it can be joined to some text: str()
- LTurn "2.5" into a decimal number: float()
int() gives a whole number, float() a decimal number and str() a string.
Tick one box.
- LA print("Score: " + 5)
A string and a number cannot be joined with +. The number has to be turned into a string first with str().
score = int(input("Score: "))
if score >= 50:
print("Pass")
else:
print("Try again")| Input | Output |
|---|---|
| 75 | |
| 50 | |
| 49 |
- LPass
- LPass
- LTry again
>= means greater than or equal to, so 50 passes and 49 does not.
Tick one box.
- LC age >= 13
13 is greater than or equal to 13.
Tick one box.
- LB A mistake in the rules of the language, so the program cannot run
A syntax error breaks the rules of Python, such as a missing bracket, so the program will not run at all.
a = input("First number: ")
b = input("Second number: ")
print(a + b)- Lint
input() gives strings, and + joins strings, so 5 and 7 make 57. int() turns each into a number so + adds them.
- LAsks for two inputs
- LConverts the inputs to integers with int()
- LPrints the correct total, for example 12 for 5 and 7
Convert each input with int() before adding, otherwise + joins the two strings.
a = int(input("First number: "))
b = int(input("Second number: "))
print(a + b)Tick one box.
- LA 7.0
7.0 has a decimal point, so it is a float.
- LIndentation shows which lines belong to the if (the block)
- LIndented lines only run when the condition is true, so wrong indentation gives an error or the wrong result
Python uses indentation to show which lines belong to the if. The indented lines only run when the condition is true, so moving a line in or out changes what the program does, or causes an IndentationError.
mark = int(input())
if mark >= 70:
print("A")
elif mark >= 50:
print("B")
else:
print("C")| Input | Output |
|---|---|
| 85 | |
| 70 | |
| 69 | |
| 12 |
- L85 and 70: A, A
- L69 and 12: B, C
70 or more prints A, so both 85 and 70 print A. 69 is at least 50, so B. 12 is C.
x = "3"
y = 4
print(int(x) * y)- L12
int("3") is 3, and 3 x 4 = 12.
Tick one box.
- LB high_score
A name cannot start with a digit, cannot contain a space and cannot be a keyword such as class.
print("Total: " + str(3 + 4))- LTotal: 7
3 + 4 is 7, str() turns it into "7", and it is joined to "Total: ".
This is an original Key Stage 3 assessment. Most questions are closed, so the marking is exact, and the written answers are marked against a mark scheme in the same style as a GCSE paper, so the format is familiar long before it counts.