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docs/reference/js/lessons/transformers/challenges.md

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+# transformers challenges
+
+Coding challenges for the transformers tutorial. #docs
+
+## Before we get started
+
+Complete the following guided tutorial:
+
+* [tutorial](/microbit/lessons/transformers/tutorial)
+
+At the end of the tutorial, click `keep editing`. Your code should look like this:
+
+```
+let inital = 5
+input.onButtonPressed("A", () => {
+    let doubled1 = double(initial)
+    basic.showNumber(doubled1, 150) // ***
+})
+```
+
+### Challenge 1
+
+Create a new function called `square` that returns the square of the number passed into the function.
+
+(Squaring means that you multiply the number by itself)
+
+```
+export function square(n: number) : number {
+    let num: number
+    return n * n
+    return num
+}
+```
+
+### Challenge 2
+
+### @video td/videos/transformers-2
+
+Add a condition for when button `B` is pressed. We will use this condition in the last challenge.
+
+```
+initial = 5
+input.onButtonPressed("A", () => {
+    let doubled = double(initial)
+    basic.showNumber(doubled, 150)
+})
+input.onButtonPressed("B", () => {
+}) // ***
+```
+
+**Challenge 3**
+
+When the `B` button is pressed, display the square of the initial value. Use the function `square`. You should get the value 25.
+