"The art of calculation is indispensable in commerce and daily life."

"What is easiest and most useful in arithmetic, such as men frequently require in cases of inheritance, legacies, partition, lawsuits, and trade."

"The science of algebra is a noble one, necessary for men."

"The unknown must be isolated to find its value."

"The Hindus have a method of calculation which they call 'the nine figures'."