Quant Interview Whiteboard Math
How to present quant interview math clearly on a whiteboard, shared editor, or scratchpad.
Candidates who need clearer live math presentation during quant interviews.
Use the board to show structure
The board should make your model visible: variables, states, events, denominators, and boundary conditions. Avoid filling space with disconnected arithmetic that hides the main idea.
Name variables simply
Use names the interviewer can track. If p is a probability, say what event it represents. If E_i is an expected time, define the state i. Clear notation prevents mistakes when follow-ups change the setup.
Keep sample spaces legible
For probability prompts, write the denominator and favorable event clearly. For cards, specify ordered or unordered. For recursion, write boundary conditions before solving. These are the lines that prevent most confusion.
Concrete board layout
For a random walk, put states and boundaries on the first line, the recurrence on the second, and the solution or intuition below. Leave room for a follow-up such as biased transition probabilities or a changed boundary.
Summarize before erasing
Before moving on, state the conclusion and the check. If the board becomes cluttered, summarize the useful structure before clearing it. The interviewer should never wonder which result you are relying on.
Common mistakes
Candidates often write equations before defining variables or scatter work across the board. A clean layout is not cosmetic; it makes the reasoning easier to inspect and repair.
Practice the pattern
Use the LeetQuidity curriculum and calibration to turn this topic into a focused practice plan.