Solve these clues to fill the grid.
- The inedible nutlike seed of the horse chestnut (plural)
- 2 Across
- An integer or a fraction
- 3 Across
- The base part of a tree that remains standing after the tree has been felled
- 4 Across
- A city in southwestern Pennsylvania where the confluence of the Allegheny River and Monongahela
- 5 Across
- A natural number that has exactly two distinct natural number divisors: 1 and itself
- 9 Across
- The divisor of a fraction
- 10 Across
- A real number that cannot be expressed as a rational number
- 11 Across
- A ridge of land that separates two adjacent river systems
- 12 Across
- All of something including all its component elements or parts
- 13 Across
- A condition characterized by behavioral and learning disorders
- 14 Across
- The dividend of a fraction
- 1 Down
- To take off or away
- 4 Down
- A number that when multiplied by itself equals a given number
- 6 Down
- One of a pair of numbers whose product is 1: the ___ of 2/3 is 3/2
- 7 Down
- Any rational or irrational number
- 8 Down
- The original amount of a debt on which interest is calculated
- 9 Down