(1) If numbers have unlike signs (one number is positive and the other number is negative), first find the difference between the two numbers (pretend the numbers are both positive), then use the sign from the larger of the two numbers.

(2) To solve a square root problem, think, "What number times itself equals this number?"

(3) When working on questions asking for answers in scientific notation, only in the last step should you convert to scientific notation. This saves time.