Click on operations to change them and click calculate/find to calculate/find values. If mobile, click type to change values, 1/2/4 to change values. If you are not mobile, you can click the change value buttons. For change value 4 you can type value and then change it to a value like value 1, per se.
I dare you to type in 3 divided by -4/5... I got an interesting answer
