Create 2 new variables called 'number' and 'nextnumber'.

We will use these to store the number that displays on the screen and the next number that the player needs to guess if it's higher or lower.

Show: How to create a variable (microbit)

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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'.

At the start of the game we're going to set the 'number' variable to a random number between 1 and 100, and we'll also set the 'nextnumber' variable to a random number between 1 and 100.

Once we've set the numbers we'll display the 'number' variable on our Microbit.

Add the following code.

let number = randint(1, 100)
let nextnumber = randint(1, 100)
basic.showNumber(number)

To play the game, the player needs to guess if the next number will be higher or lower than the number that's currently being displayed.

To guess lower they will press the A button, to guess higher they will press the B button.

Program the A button to guess lower
Add the following code to program the A button to:

1. pause half a second
2. check if the 'nextnumber' is less than or equal to 'number'
   • if it is then show the correct icon as they guessed correctly
   • else show the incorrect icon as they guessed incorrectly

input.onButtonPressed(Button.A, function () {
    basic.pause(500)
    if (nextnumber <= number) {
        basic.showIcon(IconNames.Yes)
    } else {
        basic.showIcon(IconNames.No)
    }
})

If the player guesses correctly that the next number is lower, then as well as displaying the correct icon we will give them a point. 

Add the following new code underneath the correct show icon block.

input.onButtonPressed(Button.A, function () {
    basic.pause(500)
    if (nextnumber <= number) {
        basic.showIcon(IconNames.Yes)
        basic.pause(1000)
        game.addScore(1)
        basic.pause(1000)
    } else {
        basic.showIcon(IconNames.No)
    }
})

You will find the change score by 1  block in the Advanced > Game toolbox. This block plays a little flash animation and adds 1 point to your score.

Now that the player has guessed correctly and scored a point, we need to reset the 'number' and 'nextnumber' variables so we can play the next round.

First set the 'number' variable to be the same as the 'nextnumber' variable, as this is now our starting number. Then we need to reset the 'nextnumber' variable to a random number between 0 and 100.

Finally in this step, we will display the 'number' variable on screen again so the player can make their guess. 

Add the new code underneath the pause (ms) 1000  block.

input.onButtonPressed(Button.A, function () {
    basic.pause(500)
    if (nextnumber <= number) {
        basic.showIcon(IconNames.Yes)
        basic.pause(1000)
        game.addScore(1)
        basic.pause(1000)
        number = nextnumber
        nextnumber = randint(1, 100)
        basic.showNumber(number)
    } else {
        basic.showIcon(IconNames.No)
    }
})

If the player chose lower (pressed the A button) and the next number was actually higher then we will:

1. pause 1 second
2. show what the next number was
3. pause another 1 second
4. end the game

Add the following new code underneath the incorrect show icon in the 'else' part of the block.

input.onButtonPressed(Button.A, function () {
    basic.pause(500)
    if (nextnumber <= number) {
        basic.showIcon(IconNames.Yes)
        basic.pause(1000)
        game.addScore(1)
        basic.pause(1000)
        number = nextnumber
        nextnumber = randint(1, 100)
        basic.showNumber(number)
    } else {
        basic.showIcon(IconNames.No)
        basic.pause(1000)
        basic.showNumber(nextnumber)
        basic.pause(1000)
        game.gameOver()
    }
})

The game over block ends the game, plays an animation and displays what your score was.

As the code for guessing higher is mostly the same as for guessing lower, we will duplicate the entire 'on button A pressed' group of blocks and then modify them.

1. Right click on the 'on button A pressed' and then click on 'Duplicate', this will create a copy of this group of blocks.
2. Drag the new blocks into an area that has some clear space.

Now we need to make 2 changes to the new code we duplicated:

1. Change the button in the 'on button A pressed' to be the B button.
   
2. As they're guessing higher we need to set the condition of the if block to check if the 'nextnumber' variable is higher than the 'number' variable.
   

Those are the only 2 changes you need to make to the 'on button B pressed' group of blocks, the scoring and game over is the exact same.

input.onButtonPressed(Button.B, function () {
    basic.pause(500)
    if (nextnumber >= number) {
        basic.showIcon(IconNames.Yes)
        basic.pause(1000)
        game.addScore(1)
        basic.pause(1000)
        number = nextnumber
        nextnumber = randint(1, 100)
        basic.showNumber(number)
    } else {
        basic.showIcon(IconNames.No)
        basic.pause(1000)
        basic.showNumber(nextnumber)
        basic.pause(1000)
        game.gameOver()
    }
})