Let the variable "x" represent the unknown number.
Remember "of" means to multiply, and to change a percentage into a decimal, divide the number by 100 (move decimal place two times to the left) then drop the decimal sign.
For the first question: 10% of what number is 14?
10% as a decimal is 0.1
0.1*x = 14
Divide both sides by 0.1.
x = 140
Hope that helps! Please comment if you have further questions or if you want me to do another example.
