Subject: Algebra and how to balance equations Name: Della Who are you: Other I'm a grandparent trying to help my grandkids with algebra. It's been awhile so I have forgotten some basics With the following equations, how do you know whether you need to apply the multiplication or division rule of equality? 75% t = 18 120% w = 72 Thanks Hi Della I like your use of the word balance as this is exactly the way you can think of these equations. For example consider your first equation. There are two sides and a balance point (equal sign) between them. The task is to manipulate the quantities on the two sides, all the time maintaining the balance, and conclude with the variable t alone on one side and a number on the other. The first task is to interpret 75%. the term "percent" means per one-hundred so 75% is the fraction 75/100. Hence the first equation can be written   75/100 t = 18 or in decimal form 0.75 t = 18. To manipulate the equation, maintain the balance and leave t alone on the left side you can divide both sides by 0.75. Thus 0.75 t/0.75 = 18/0.75 which is t = 24. Penny