This is a simple calculator. Press the green flag to start. When you round, type in the number you round, then click the round button before typing in the number you want to round to. When using the square root (√), type in the number you want to go to the square root of and then, click the √ button. The ~⬛ button means the nearest square. Click the slide button to go on to the next section. Click the del button to delete your number.
Click SLIDE to go into the next section of maths. There are 5 sections. Thanks to @somerndscratchuser for correcting me on the PHI symbol. I thought it was ø but it was actually Φ.