7. You press and hold down the Alt button on your keyboard and then type 251 on your number pad located to the right of your keyboard. Or if it’s a hand held calculator you switch to secondary function and locate the symbols in red/blue underneath the original key.
8. Plug in your answer back into the the problem or invert the question so like instead of addition you subtract the product from one of the subjects in the original equation.
9. You can type a fraction into a calculator by placing the numerator first then inserting a forward slash and then your denominator.
I hope that helps, let me know if you have any more questions. Have a good day!