All you have to do is type in the method you would like to use ( addition, subtraction, multiplication or division ) and then type in the first number in the number sentence and then the other. The Scratchtastic Calculator will give you the answer in less that a second!
This project is mobile friendly, by the way, but it is highly recommended to use a computer or an iPad with a large screen. But it’s your choice! Make sure you have fun! :D