1. Scientific notation – A number between 1 and 10 multiplied by a power of 102. Parallel lines – Two or more lines which are always the same distance apart3. Expanded notation – Pointing out the place value of a digit4. Acute triangle – A triangle containing only acute angles5. Common denominator – A number that can be divided evenly by all the denominators in the problem6. Least common multiple – The smallest multiple that is common to two or more numbers7. Ordered pair – Any pair of elements (x, y) where the first element is x and the second is y8. Perpendicular lines – Two lines which intersect at right angles9. Adjacent angles – Angles with a common side and vertex10. Greatest common factor – The largest factor that is common to two or more numbers