🐍 Python from scratch · Session 4

Making decisions: if, elif and else: practice sheet

Name ____________________Date __________Score ____ / 25

← Back to the lesson

Part 1: Questions with True or False answers

Remember: A comparison gives True or False. == asks "equal?", != "not equal?", and < > <= >= compare sizes.

1. Warm-up x = 15. Print whether x is greater than 10, then whether x equals 15.
```
x = 15
```
2. Core a = 7 and b = 7. Print whether they are equal, then whether they are different.
```
a = 7
b = 7
```
3. Stretch 🔥 n = 24. Print whether n is even, then whether n is a multiple of 3.
```
n = 24
```

Part 2: if and else

Remember: if condition: runs the indented lines only when the condition is True; else: runs when it is False.

4. Warm-up temp = 30. Print Hot if temp is above 25, otherwise Not hot.
```
temp = 30
```
5. Core n = 7. Print even or odd.
```
n = 7
```
6. Stretch 🔥 pin = 4821. Print Access granted if pin is 4821, otherwise Wrong PIN, then always print Goodbye.
```
pin = 4821
```

Part 3: Many choices with elif

Remember: elif adds more cases between if and else. Python checks from the top and runs only the first True one.

7. Warm-up speed = 45. Print Slow below 30, Normal below 60, otherwise Fast.
```
speed = 45
```
8. Core n = -4. Print positive, negative or zero.
```
n = -4
```
9. Stretch 🔥 Ticket price by age: under 5 free (Price: 0), under 13 Price: 100, 60 or over Price: 120, everyone else Price: 200.
```
age = 30
```

Part 4: and, or, not

Remember: and is True only when both sides are True; or when at least one is; not flips True and False.

10. Warm-up day = "Sunday". Print Holiday! on Saturday or Sunday, otherwise School day.
```
day = "Sunday"
```
11. Core Print Ride if height is at least 120 and age at least 8, otherwise No ride.
```
height = 130
age = 9
```
12. Stretch 🔥 Leap year, full rule: divisible by 4 and not by 100, or divisible by 400. Print leap or not leap.
```
y = 2024
```

Activity 1: The grade machine

13. Print Grade: A for 90 or more, B for 75 to 89, C for 50 to 74 and D below 50. It will be tested with many marks.
1. Write if marks >= 90: and print Grade: A.
2. Add elif for B (75 or more).
3. Add elif for C (50 or more).
4. Add else for D.
5. Test 90, 75, 50 and 49 yourself.
```
marks = 82

# Step 1 to 4
```

Activity 2: Electricity bill

14. The first 100 units cost 5 each, the next 100 cost 7 each and every unit above 200 costs 10. Print Bill: and the amount. Test with 80, 150, 200 and 250 units.
1. If units <= 100: bill = units × 5.
2. elif units <= 200: bill = 500 + (units − 100) × 7.
3. else: bill = 500 + 700 + (units − 200) × 10.
4. Print Bill: and the bill.
```
units = 150

# Steps 1 to 3: work out bill

# Step 4
```

Activity 3: Rock, paper, scissors judge

15. p1 and p2 hold rock, paper or scissors. Print Draw, Player 1 wins or Player 2 wins. Rock beats scissors, scissors beat paper, paper beats rock.
1. If p1 == p2 print Draw.
2. elif p1 beats p2 (three cases joined with or) print Player 1 wins.
3. else print Player 2 wins.
4. Test all nine pairs if you can.
```
p1 = "rock"
p2 = "scissors"

# Step 1

# Step 2

# Step 3
```

Predict the output

Work it out on paper first, then type it into the lesson page to check.

16. What does this print?
```
print(5 > 3)
```

17. What does this print?

x = 7
if x % 2 == 0:
    print("even")
else:
    print("odd")

18. What does this print?

t = 20
if t > 30:
    print("hot")
elif t > 15:
    print("warm")
else:
    print("cold")

19. What does this print?
```
print(True and False)
```
20. What does this print?
```
print(not (3 == 3))
```

21. What does this print?

age = 15
if age >= 13 or age == 9:
    print("yes")
else:
    print("no")

22. What does this print?

n = 12
r = ""
if n > 10:
    r = r + "A"
if n > 5:
    r = r + "B"
print(r)

Homework

23. Warm-up year = 2024. Print leap if it is divisible by 4, else not leap (simple rule).
```
year = 2024
```
24. Core a, b and c are three numbers. Print the largest.
```
a = 4
b = 9
c = 2
```
25. Stretch 🔥 Three sides of a triangle. Print equilateral, isosceles or scalene (or not a triangle if one side is at least the sum of the other two).
```
a = 3
b = 4
c = 5
```

Answer key

```
x = 15
print(x > 10)
print(x == 15)
```
```
a = 7
b = 7
print(a == b)
print(a != b)
```

n = 24
print(n % 2 == 0)
print(n % 3 == 0)

temp = 30
if temp > 25:
    print("Hot")
else:
    print("Not hot")

n = 7
if n % 2 == 0:
    print("even")
else:
    print("odd")

pin = 4821
if pin == 4821:
    print("Access granted")
else:
    print("Wrong PIN")
print("Goodbye")

speed = 45
if speed < 30:
    print("Slow")
elif speed < 60:
    print("Normal")
else:
    print("Fast")

n = -4
if n > 0:
    print("positive")
elif n < 0:
    print("negative")
else:
    print("zero")

age = 30
if age < 5:
    print("Price: 0")
elif age < 13:
    print("Price: 100")
elif age >= 60:
    print("Price: 120")
else:
    print("Price: 200")

day = "Sunday"
if day == "Saturday" or day == "Sunday":
    print("Holiday!")
else:
    print("School day")

height = 130
age = 9
if height >= 120 and age >= 8:
    print("Ride")
else:
    print("No ride")

y = 2024
if (y % 4 == 0 and y % 100 != 0) or y % 400 == 0:
    print("leap")
else:
    print("not leap")

marks = 82
if marks >= 90:
    print("Grade: A")
elif marks >= 75:
    print("Grade: B")
elif marks >= 50:
    print("Grade: C")
else:
    print("Grade: D")

units = 150
if units <= 100:
    bill = units * 5
elif units <= 200:
    bill = 500 + (units - 100) * 7
else:
    bill = 500 + 700 + (units - 200) * 10
print("Bill:", bill)

p1 = "rock"
p2 = "scissors"
if p1 == p2:
    print("Draw")
elif (p1 == "rock" and p2 == "scissors") or (p1 == "scissors" and p2 == "paper") or (p1 == "paper" and p2 == "rock"):
    print("Player 1 wins")
else:
    print("Player 2 wins")

True
odd
warm
False
False
yes
AB

year = 2024
if year % 4 == 0:
    print("leap")
else:
    print("not leap")

a = 4
b = 9
c = 2
if a >= b and a >= c:
    print(a)
elif b >= c:
    print(b)
else:
    print(c)

a = 3
b = 4
c = 5
if a >= b + c or b >= a + c or c >= a + b:
    print("not a triangle")
elif a == b and b == c:
    print("equilateral")
elif a == b or b == c or a == c:
    print("isosceles")
else:
    print("scalene")