pxt-calliope/docs/lessons/counter/quiz-answers.md

counter quiz answers

Learn how to create a counter with the BBC micro:bit button.

This is the answer key for the counter quiz.

1. What is a variable?

Answers may vary but a variable is a place where you can store and retrieve data

2. Draw the stored value for the variable called count

let count = 0

We create a variable, count to keep track of the current count. The number 0 is stored into memory of the variable.

3. Draw which LEDs are ON after running this code and pressing button "A" once. Explain you chose to draw that number

let count_ = 0
input.onButtonPressed("A", () => {
    count_ = count_ + 1
    basic.showNumber(count, 150)
})

We are only pressing on button pressed once. So the number to display on the micro:bit is also one.

4. Draw which LEDs are ON after running this code and pressing button "A" three times. Explain you chose to draw that number

count_ = 0
input.onButtonPressed("A", () => {
    count_ = count_ + 1
    basic.showNumber(count_, 100)
})

We included the code on button pressed("A") that runs each time the user presses A. The code increments count by 1. We increase count by 1 whenever the user presses the button. So the third time the A button is pressed on the BBC micro:bit, the number 3 is displayed