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Quiz: Variables and Numbers

Test your understanding of variables, integers, floats, and naming rules with these questions. Click "Show Answer" to reveal the correct answer and explanation.

1. What is a variable in Python?

  1. A word that Python reserves for its own use
  2. A labeled storage location that holds a value in your program's memory
  3. A type of loop that repeats a block of code
  4. A special symbol used to write comments
Show Answer

The correct answer is B. A variable is a labeled storage location in your program's memory. You give it a name, store a value inside it, and Python remembers that value for you. Think of it like a sticky note with a name on the front and the current value on the back — when you need it, you look it up by name.

Concept Tested: Variable Assignment

2. What does the = sign mean in the Python statement score = 10?

  1. Check whether score is equal to 10
  2. Add 10 to the current value of score
  3. Store the value 10 in the variable named score
  4. Print the number 10 to the output area
Show Answer

The correct answer is C. In Python, = is the assignment operator — it means "take the value on the right and store it in the variable on the left." It is a one-way instruction; the value flows from right to left. It does not mean "is equal to" the way it does in math — that comparison uses == (two equals signs).

Concept Tested: Variable Assignment

3. Which variable name follows Python's snake_case naming convention?

  1. MyScore
  2. my-score
  3. myscore
  4. my_score
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The correct answer is D. Snake_case joins words with underscores and keeps all letters lowercase: my_score. MyScore uses capital letters (that is camelCase or PascalCase). my-score uses a dash, which Python reads as subtraction. myscore runs the words together with no separator, making it harder to read.

Concept Tested: Variable Naming (snake_case)

4. What kind of number is 3.14 in Python?

  1. An integer (int)
  2. A string (str)
  3. A float (float)
  4. A boolean (bool)
Show Answer

The correct answer is C. Any number with a decimal point is a float (short for floating-point number) in Python. Integers are whole numbers with no decimal point. 3.14 has a decimal point, so Python stores it as a float. You use floats for measurements, money, and values that do not land exactly on a whole number.

Concept Tested: Floats

5. What will Python print when this code runs?

1
2
3
score = 10
score = 25
print(score)
  1. 10
  2. 25
  3. 10 and then 25 on two lines
  4. An error, because you cannot assign to a variable twice
Show Answer

The correct answer is B. Python reads each line in order. First it stores 10 in score, then it replaces that value with 25. When print(score) runs, the variable holds 25. There is no error — reassigning a variable is completely normal and is how programs update values as they run.

Concept Tested: Variable Reassignment

6. Which variable name would cause a Python error?

  1. player_score
  2. _hidden
  3. 1st_place
  4. total_points
Show Answer

The correct answer is C. Variable names cannot start with a digit. 1st_place begins with 1, so Python raises a SyntaxError. Variable names must start with a letter or an underscore. player_score, _hidden, and total_points all follow that rule and are valid names.

Concept Tested: Variable Naming Rules

7. What does Python print when you divide two integers using /?

1
2
result = 10 / 2
print(result)
  1. 5 (an integer)
  2. 5.0 (a float)
  3. 10/2 (a fraction)
  4. An error, because you cannot divide integers
Show Answer

The correct answer is B. In Python 3, dividing with / always returns a float, even when the result is a whole number. So 10 / 2 gives 5.0, not 5. If you want a whole-number result, use the floor division operator // instead: 10 // 2 gives 5.

Concept Tested: Floats

8. What is the value of None in Python?

  1. The integer zero (0)
  2. An empty string with no characters ("")
  3. A special value meaning "no value yet" or "nothing here"
  4. The boolean value False
Show Answer

The correct answer is C. None is a special Python value of type NoneType that means "no value" or "nothing here." It is different from 0 (an integer), "" (an empty string), and False (a boolean) — each of those is something, whereas None means the absence of any value at all.

Concept Tested: None Value

9. What is wrong with the variable name my-score?

  1. It is too long and will slow down the program
  2. Python reads the dash as a minus sign and thinks you are subtracting two variables
  3. Variable names must start with a capital letter
  4. You cannot use the letter y in a variable name
Show Answer

The correct answer is B. The dash - is Python's subtraction operator. When Python sees my-score, it reads it as the variable my minus the variable score, not as a single name. This causes a NameError because my and score have not been defined. Always use an underscore _ to join words in a variable name.

Concept Tested: Variable Naming Rules

10. Which of the following best describes when to use an integer versus a float?

  1. Always use floats — they are more accurate than integers
  2. Use integers for things you count (sides, lives, score) and floats for measurements or decimals
  3. Use integers for text and floats for numbers
  4. Use floats in the first half of a program and integers in the second half
Show Answer

The correct answer is B. Integers (int) are for countable whole things — number of lives, game score, number of sides on a shape. Floats (float) are for values that can have decimal parts — heights, prices, percentages, pi. Choosing the right type makes your code clearer and avoids unexpected decimal results.

Concept Tested: Integers