You need to set up a proportion. Percents always over percents, so our first fraction would be , which just means that out of 100%, we are given 84. We need to find a variable to solve for: x. We need to find the number that <em>is </em>84% of 300, which means that 300 is 100%. Knowing this, it would be in the denominator, since both 100 and 300 are 100% of something. This would give us the fraction . I like to use the cross-multiply method, which just means you multiply by a diagonal and then divide by what's left. This would give us 300 x 84 = 25,200/100 = 252. Hope this helps!