Python Number Power

Requirements Checklist

• Ask user for total responses
• Ask for 1 category of responses
• Store both as numeric variables
• Calculate percentage accurately
• Use round() for 1 decimal
• Print clean readable sentence
• Stretch: Calculate Yes & No %

Code Blueprint / Written Program calculator.py

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Sample Terminal Output:

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Exit Ticket (Show What You Know)

1. Difference between integer and float:

2. Why use float() instead of int() for input?

3. Python formula for calculating a percentage:

4. What does round(number, 1) do?

Python Quick Cheat Sheet

int()

Converts value to a whole number

float()

Converts value to a decimal number

input()

Captures user response as string text

print()

Displays text & variable outputs

round()

Limits decimals: round(val, n)

Model Output (e.g. Total = 19, Yes = 13): 13 / 19 * 100 = 68.421... → Rounded output displays cleanly as: 68.4.

Turn to Page 2 for Debugging Solutions, Project Rubric, and Exit Ticket Key →

Teacher Solutions Guide • Parts 3, 4 & 5

Computing Foundations

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Part 3 Solutions: Debugging Challenges

Challenge #1: Price Input Bug

Diagnosis: price is stored as a string. Multiplying a string by 0.07 throws a TypeError: can't multiply sequence by non-int of type 'float'.

Corrected Line 1: price = float(input("Enter the price: ")) Use float() because prices often contain cents (e.g. 19.99).

Challenge #2: Incomplete Math Logic

Diagnosis: The program runs without syntax errors, but produces 0.6, which is a decimal proportion/fraction, not a percentage out of 100.

Corrected Line: percent = yes / total * 100 Output will be 60.0% instead of 0.6.

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Part 4 Exemplar: Mini Survey Calculator

Model Solution Code (Includes Stretch Goal)

total = int(input("Total survey responses: "))

yes_votes = int(input("Number of YES votes: "))

no_votes = total - yes_votes

yes_pct = round(yes_votes / total * 100, 1)

no_pct = round(no_votes / total * 100, 1)

print("Survey Results: ", yes_pct, "% Yes | ", no_pct, "% No")

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Part 5 Solutions: Exit Ticket

1. Difference between int and float:

An int is a whole number without decimals (e.g., 5, -2); a float represents numbers with decimal points (e.g., 5.0, 3.14).

2. Why use float() instead of int() for input?

Use float() whenever the user might enter decimal amounts (like prices, heights, weights, or averages) to prevent a ValueError.

3. Python formula for a percentage:

part / whole * 100

Note: division happens before multiplication according to standard precedence.

4. What does round(number, 1) do?

Rounds the given floating-point number to exactly 1 decimal place (tenths place) for cleaner presentation.

3 Critical Misconceptions to Watch For

1. Forgetting Casts Students often write total = input(...) and assume it is a number. Remind them input() always returns a string.

2. Average Parentheses Writing a + b + c / 3 divides only c. Remind students that Python obeys PEMDAS: (a + b + c) / 3.

3. Missing * 100 Students often confuse the decimal ratio (0.75) with the percent value (75.0%).