Review of Grades 5–6 topics

One percent is one hundredth of a number: 1% = 1/100. To find p percent of a number, multiply it by p/100; to find the whole when its percent is known, divide the part by p and multiply by 100. A proportion is an equality a : b = c : d; its basic property says that the product of the middle terms equals the product of the extreme terms: b · c = a · d. The arithmetic mean of several numbers is their sum divided by how many numbers there are. When multiplying rational numbers, equal signs give a positive result and different signs give a negative one. In a simple equation we find the unknown term by using the inverse operation.