We're going to count to 2 minutes (or 120 seconds) so we need a variable to store the seconds as they tick by.

Create a variable called 'seconds'.

Microbit: How to create a variable

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In the Variables toolbox, create a new variable by clicking the 'Make a Variable' button.

Once you click this button a box will appear asking what you want to call your variable. Give it a name that reminds you what you will be using it for. For example, if you wanted to keep track of your score in a game, you would create a variable called 'score'.

To start the toothbrush timer you will need to press the A button. So we will show an arrow pointing left (west) at the start. This will point at the A button.

You will find these blocks in the Advanced > Images toolbox.

Note: Change the arrow image to West (North is displayed in the code below).

images.arrowImage(ArrowNames.West).showImage(0)

Next we will program the A button to set the 'seconds' variable to 0 and then count to 120.

We do this by using a 'while' loop block. While the 'seconds' variable is less than or equal to 120, pause 1 second and then add 1 to the 'seconds' variable. This will keep adding 1 to the 'seconds' variable until it reaches 120.

input.onButtonPressed(Button.A, function () {
    seconds = 0
    while (seconds <= 120) {
        basic.pause(1000)
        seconds += 1
    }
})