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Expert Tutor: Math, SAT/ACT/GRE/PSAT, SQL, Python, VBA, Excel & Linux
David L.

4.9 (2,041 ratings)

5,847 hours tutoring

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Hourly rate: $38

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About David

Bio

Why I'm a good tutor:
* I know my material. That's how I got a Physics PhD and excelled at software tech support.
* Patience, empathy and praise for my students.
* I love questions, since they point to where the trouble is. I answer using very specific examples, illustrating general principles and techniques.
It's too easy to not give enough examples, or leave terms undefined or ambiguous.
* I love teaching and helping people.
* I use my whimsical sense of humor to have some fun...

Why I'm a good tutor:
* I know my material. That's how I got a Physics PhD and excelled at software tech support.
* Patience, empathy and praise for my students.
* I love questions, since they point to where the trouble is. I answer using very specific examples, illustrating general principles and techniques.
It's too easy to not give enough examples, or leave terms undefined or ambiguous.
* I love teaching and helping people.
* I use my whimsical sense of humor to have some fun ("pretend that lumpy thing I just drew is a circle").
* I make tutoring a conversation, where I show 1-2 steps, and ask if that was clear. Occasionally, I'm not clear enough, so I rephrase!

I tutor in 3 areas:

MATH
* 18 years of tutoring Algebra 1 thru Calculus.

TEST PREP
* Preparing students for the Math and Science sections of the SAT, the GRE, the ACT, and the PSAT.

SOFTWARE
* I teach complete SQL courses, including joins and subqueries.
I have MySQL, PostgreSQL, SQL Server & Oracle servers ready to go.
In 5 minutes, I can get you practicing SQL on SQLite on your computer.
* Python, including web scraping (with Selenium) and working with databases. Sorry, no Data Science or Pandas.
* Linux, Bash scripting, awk, sed, grep & regular expressions.
* I've done many insane things with Microsoft Excel and VBA.

I've been told I'm great at communicating with people at any level of understanding.
I'll put you at ease, and happy to work at your pace.

Here's how many hours I've tutored on Wyzant.com:
Python: 2,032
SQL & Databases: 1,840
Linux & Unix: 495
VBA: 443
Excel (no VBA): 345
SAT Math, ACT Math, ACT Science, and GRE Quant: 286
Calculus, precalculus, and other math topics: 435

For regular or Instant Book sessions, I charge only for the time used, not the time reserved.
If you postpone or cancel regular or Instant Book sessions nicely, I'll void the charge. If you're not nice or blow me off, I may charge 100%.

Read more

Education

University of California, Los Angeles (UCLA) - BS
Physics
U.C. Berkeley - Physics
PhD

Policies

  • Hourly Rate: $38
  • Rate details: For regular or Instant Book sessions, I charge only for the time used. If you postpone or cancel regular or Instant Book sessions nicely, I'll void the charge. Otherwise, I may charge 100%.
  • Lesson cancellation: 3 hours notice required

  • Background check passed on 1/31/2024

  • Your first lesson is backed by our Good Fit Guarantee

Schedule

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Approved Subjects

ACT Math

ACT Math

I've helped many students improve their scores on the math sections of the ACT, SAT, PSAT, and GRE, plus ACT Science. I am very good at teaching and making students feel comfortable. To get great scores, here's what students need: 1. To know the math topics that always appear on these tests. 2. To manage their time and do problems quickly. 3. To know the typical pitfalls and shortcuts on these tests. When we are done, they will feel more confident. My work with students is divided into two phases. In phase 1, the student and I go through a practice test together. When the student struggles with or can't do a problem, I use that as an opportunity to teach the student the math and problem-solving techniques involved in that problem. All students have gaps in their understanding of math and problem-solving techniques. In phase 2, I give the student a set of practice tests to take timed, under simulated testing conditions, on their own. Here, they learn how to manage time pressure, how to pace themselves, and how to avoid spending too much time on any one problem. In phase 2, I also ask students to keep track of problems they have trouble with, so that we can review them together, to continue improving their command of math and problem-solving techniques. I've worked with students who are neurodivergent or are not native English speakers.
Algebra 1

Algebra 1

I have 15 years of experience tutoring students in math, from pre-algebra to calculus, and in the math sections of the ACT, the GRE, and the SAT. On Wyzant, I've tutored for 518 hours in various topics in math. I've helped math students with a variety of difficulties, such as math anxiety, making lots of mistakes on homework and tests, and teachers and textbooks that were not so good. I've been told I'm kind and really good at communicating with people at their own level. I'm also patient, happy to work with students at a comfortable pace, and good at putting students at ease. When I tutor over the internet, I use an iPad to write on the Wyzant whiteboard. After the session, I can send you screenshots of the whiteboard.
Algebra 2

Algebra 2

I have 15 years of experience tutoring students in math, from pre-algebra to calculus, and in the math sections of the ACT, the GRE, and the SAT. On Wyzant, I've tutored for 518 hours in various topics in math. I've helped math students with a variety of difficulties, such as math anxiety, making lots of mistakes on homework and tests, and teachers and textbooks that were not so good. I've been told I'm kind and really good at communicating with people at their own level. I'm also patient, happy to work with students at a comfortable pace, and good at putting students at ease. When I tutor over the internet, I use an iPad to write on the Wyzant whiteboard. After the session, I can send you screenshots of the whiteboard.
AMC (Competition math)

AMC (Competition math)

I was on my high school's math team, and participated in many math competitions, including the 1981 US Math Olympiad. I credit that work as laying part of the foundation I used to get my Physics Ph.D. from UC Berkeley. I also have more than 15 years of experience tutoring students in math, from Algebra 1 to Calculus. High school-level competition math does not use any new math concepts. Instead, it requires more creative applications of the math you already know. Copies of past years' AMC competitions (and solutions) are available online for free. I use these when tutoring competition math. If you want to take your math ability to the next level, I'd be happy to help.
Calculus

Calculus

I have 15 years of experience tutoring students in math, from pre-algebra to calculus, and in the math sections of the ACT, the GRE, and the SAT. On Wyzant, I've tutored for 518 hours in various topics in math. I've helped math students with a variety of difficulties, such as math anxiety, making lots of mistakes on homework and tests, and teachers and textbooks that were not so good. I've been told I'm kind and really good at communicating with people at their own level. I'm also patient, happy to work with students at a comfortable pace, and good at putting students at ease. When I tutor over the internet, I use an iPad to write on the Wyzant whiteboard. After the session, I can send you screenshots of the whiteboard.
GRE

GRE

I've helped many students improve their scores on the math/quant sections of the GRE, SAT, ACT, and PSAT. I'm sorry, but I don't help with the Verbal Reasoning section. I am very good at teaching and making students feel comfortable. To get great scores, here's what students need: 1. To know the math topics that always appear on these tests. 2. To manage their time and do problems quickly. 3. To know the typical pitfalls and shortcuts on these tests. When we are done, they will feel more confident. My work with students is divided into two phases. In phase 1, the student and I go through a practice test together. When the student struggles with or can't do a problem, I use that as an opportunity to teach the student the math and problem-solving techniques involved in that problem. All students have gaps in their understanding of math and problem-solving techniques. In phase 2, I give the student a set of practice tests to take timed, under simulated testing conditions, on their own. Here, they learn how to manage time pressure, how to pace themselves, and how to avoid spending too much time on any one problem. In phase 2, I also ask students to keep track of problems they have trouble with, so that we can review them together, to continue improving their command of math and problem-solving techniques. I've worked with students who are neurodivergent or are not native English speakers.
Linux

Linux

I have tutored 479 hours in Linux, UNIX, Bash, and Bash scripting on Wyzant. I have years of work and tutoring experience with the Linux/UNIX command line and with shell scripting, including with sed, awk, grep, and regular expressions/regex. I have experience working with Ubuntu Desktop and Server, RedHat/CentOS, Kali, and Debian. I have imported and installed a variety of Linux distros into virtual machines in Virtualbox and VMWare on Windows hosts, and have networked together multiple Virtualbox guests running in parallel. I do not tutor C/C++ programming.
Microsoft Excel

Microsoft Excel

I have tutored Excel for 303 hours on Wyzant, not including my VBA tutoring. I have many years of experience with Excel, doing all sorts of insane things with it: * using Solver for the maximal flow, shortest route, and resource allocation problems you see in business classes * pivot tables, including pivot tables of the output of other pivot tables * chains of spreadsheet functions * statistical analyses * charts and tables * custom spreadsheet functions written in VBA * custom windows with hundreds of lines of VBA code. I have a talent for two things: 1) seeing where my students are, and then 2) telling them what they need to know in an easy-to-understand way at a comfortable pace.
Microsoft Windows

Microsoft Windows

I'm an experienced software technical support engineer who has worked with all versions of Windows since Windows 3.11. I have done extensive troubleshooting of problems with the Windows operating system and of programs running on Windows, including problems with slowness, crashing, errors, and malware.
Precalculus

Precalculus

I have 15 years of experience tutoring students in math, from pre-algebra to calculus, and in the math sections of the ACT, the GRE, and the SAT. On Wyzant, I've tutored for 518 hours in various topics in math. I've helped math students with a variety of difficulties, such as math anxiety, making lots of mistakes on homework and tests, and teachers and textbooks that were not so good. I've been told I'm kind and really good at communicating with people at their own level. I'm also patient, happy to work with students at a comfortable pace, and good at putting students at ease. When I tutor over the internet, I use an iPad to write on the Wyzant whiteboard. After the session, I can send you screenshots of the whiteboard.
Probability

Probability

I have 15 years of experience tutoring students in math, from pre-algebra to calculus, and in the math sections of the ACT, the GRE, and the SAT. On Wyzant, I've tutored for 518 hours in various topics in math. I've helped math students with a variety of difficulties, such as math anxiety, making lots of mistakes on homework and tests, and teachers and textbooks that were not so good. I've been told I'm kind and really good at communicating with people at their own level. I'm also patient, happy to work with students at a comfortable pace, and good at putting students at ease. When I tutor over the internet, I use an iPad to write on the Wyzant whiteboard. After the session, I can send you screenshots of the whiteboard.
PSAT

PSAT

I've helped many students improve their scores on the math sections of the PSAT, SAT, ACT, and GRE. I'm sorry, but I don't help with the Reading and Writing section. I am very good at teaching and making students feel comfortable. To get great scores, here's what students need: 1. To know the math topics that always appear on these tests. 2. To manage their time and do problems quickly. 3. To know the typical pitfalls and shortcuts on these tests. When we are done, they will feel more confident. My work with students is divided into two phases. In phase 1, the student and I go through a practice test together. When the student struggles with or can't do a problem, I use that as an opportunity to teach the student the math and problem-solving techniques involved in that problem. All students have gaps in their understanding of math and problem-solving techniques. In phase 2, I give the student a set of practice tests to take timed, under simulated testing conditions, on their own. Here, they learn how to manage time pressure, how to pace themselves, and how to avoid spending too much time on any one problem. In phase 2, I also ask students to keep track of problems they have trouble with, so that we can review them together, to continue improving their command of math and problem-solving techniques. I've worked with students who are neurodivergent or are not native English speakers.
Python

Python

I have tutored Python for 1986 hours on Wyzant, at all levels of experience with Python and programming. I've done a wide variety of Python programming. I've worked with:many of the basic Python libraries, with web scraping (mostly Selenium), database programming, and object-oriented programming. I have 15 years of experience as a tutor of math and software, and 10 years as a Technical Support Engineer. I have a talent for understanding what my students need to know, and teaching them at their own pace. I often teach students whose first programming language is Python. I teach them: 1) The basics of Python. 2) The basic programming structures and strategies that people learn with their first programming language. 3) How to understand and fix errors, including basic troubleshooting techniques. 4) How to find Python information and code samples on the internet. I've posted some of my Python programs online on GitHub, at github.com/DavidJLambert. Personally, I use PyCharm, Thonny, and Jupyter Notebook, but I'll help you no matter how you write and run Python. I also have programmed in VBA, Bash scripting, Java, and Fortran (though I'm too rusty at Java and Fortran to tutor those). I don't teach complete Python classes. I help people who have specific Python questions, or who need help with a Python course they're taking. I teach by programming incrementally. I'll start with a little Python, add print statements so you can see what it does, and run it, fixing any issues. Then I'll remove the old print statements, add a little more Python, add new print statements so you can see what the new code does, and run it again, fixing any new issues. I keep repeating this cycle until the Python does exactly what I want it to do. It can be tempting to write all your code first and test it all later, but that often results in a whole tangle of errors, and if you gave the program the wrong structure, you'll have to redo a lot of your coding.
Quantum Physics

Quantum Physics

I've taken Quantum Mechanics courses at UCLA and UC Berkeley. I also took courses in atomic, nuclear, and particle physics courses at UCLA, and one year of particle physics at UC Berkeley. My doctoral dissertation was in particle physics, titled "Study Of b Anti-b Production In e+ e- Annihilation At s**(1/2) = 29 Gev With The Aid Of Neural Networks", using data collected at the Stanford Linear Accelerator Center. If you want help with quantum physics, please let me know what you want help with, and if I can help, we can meet. You should know that there are many misconceptions about quantum physics, and if I you repeat one to me, I will gently tell you how that's a misconception, and I will tell you why.
SAT Math

SAT Math

I've helped many students improve their scores on the math sections of the SAT, ACT, PSAT, and GRE, plus ACT Science. I am very good at teaching and making students feel comfortable. To get great scores, here's what students need: 1. To know the math topics that always appear on these tests. 2. To manage their time and do problems quickly. 3. To know the typical pitfalls and shortcuts on these tests. When we are done, they will feel more confident. My work with students is divided into two phases. In phase 1, the student and I go through a practice test together. When the student struggles with or can't do a problem, I use that as an opportunity to teach the student the math and problem-solving techniques involved in that problem. All students have gaps in their understanding of math and problem-solving techniques. In phase 2, I give the student a set of practice tests to take timed, under simulated testing conditions, on their own. Here, they learn how to manage time pressure, how to pace themselves, and how to avoid spending too much time on any one problem. In phase 2, I also ask students to keep track of problems they have trouble with, so that we can review them together, to continue improving their command of math and problem-solving techniques. I've worked with students who are neurodivergent or are not native English speakers.
SQL

SQL

SELECTs with all join types, subqueries, Window functions, bind variables, and SQL UNNEST. I also teach stored procedures & triggers. I have Oracle, SQL Server, MySQL, PostgreSQL, and SQLite databases. I've installed and worked extensively with: * Oracle, PL/SQL, and SQL Developer * SQL Server, T-SQL, and SQL Server Management Studio (SSMS) * PostgreSQL, PL/pgSQL, and pgAdmin * MySQL and MySQL Workbench * SQLite * Microsoft Access (sorry, no forms or reports) I've also helped professionals with Google BigQuery, Snowflake, and Teradata. I've migrated Microsoft's Northwind Database to SQLite, and in 5 minutes I can set it up on your computer to practice on. On Wyzant, I have tutored SQL and databases for 1986 hours. I have 11 years of work experience with SQL and Databases. I've written Python and VBA that generates SQL for interacting with databases.
Trigonometry

Trigonometry

I have 15 years of experience tutoring students in math, from pre-algebra to calculus, and in the math sections of the ACT, the GRE, and the SAT. On Wyzant, I've tutored for 518 hours in various topics in math. I've helped math students with a variety of difficulties, such as math anxiety, making lots of mistakes on homework and tests, and teachers and textbooks that were not so good. I've been told I'm kind and really good at communicating with people at their own level. I'm also patient, happy to work with students at a comfortable pace, and good at putting students at ease. When I tutor over the internet, I use an iPad to write on the Wyzant whiteboard. After the session, I can send you screenshots of the whiteboard.
UNIX

UNIX

I have tutored 479 hours in Linux, UNIX, Bash, and Bash scripting on Wyzant. I have years of work and tutoring experience with the Linux/UNIX command line and with shell scripting, including with sed, awk, grep, and regular expressions/regex. I have experience working with Ubuntu Desktop and Server, RedHat/CentOS, Kali, and Debian. I have imported and installed a variety of Linux distros into virtual machines in Virtualbox and VMWare on Windows hosts, and have networked together multiple Virtualbox guests running in parallel. I do not tutor C/C++ programming.
Visual Basic

Visual Basic

I have tutored VBA on Wyzant for 408 hours. I have taught VBA to lots of people: * many students new to programming, * working professionals needing help with advanced VBA * students doing the Stock Ticker VBA assignment. I've also helped professionals make slow macros run 10-100 times faster. I have written custom worksheet functions, VBA that uses SQL to interact with databases, VBA that uses Selenium to do web scraping, and tons of VBA for custom functionality in Excel, Access, and Outlook, sometimes with custom forms with buttons, list boxes, etc. I only work with VBA and VBScript, not with the .NET version of Visual Basic.

Examples of Expertise

David has provided examples of their subject expertise by answering 47 questions submitted by students on Wyzant’s Ask an Expert.

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David L.'s Photo

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Ratings and Reviews

Rating

4.9 (2,041 ratings)
5 star
(1,895)
4 star
(70)
3 star
(32)
2 star
(11)
1 star
(33)

Reviews

An extremely knowledgeable tutor I highly recommend.

David taught me about primary and foreign keys in SQL. He pulled up a database he already had, was ready to teach me to code immediately, and explained everything he did. It was money well spent, and I will continue to learn more and more. I am hiring him again for tutoring. I was thrilled with his tutoring skills.

Consuela, 2 lessons with David

Great Learning Experience

I had a great session with David. He was very knowledgeable with SQL, explained concepts clearly, and provided practical examples that made things easy to understand. He was also extremely helpful and accommodating, making sure to address all my questions. Highly recommend working with him!

Amanda, 3 lessons with David

Multiple Column Array

I want to give the highest praise to David L for successfully solving an incredibly complex programming challenge. The task involved building a fully automated data input and output system capable of handling an array of 2,500 rows by 20 columns — no small feat by any measure. Not only did he complete it flawlessly, but he also did it with a level of precision, efficiency, and elegance that exceeded all expectations. David is exceptionally talented. His technical expertise, problem-solving skills, and deep understanding of automation and data handling are truly world-class. But what makes working with him even better is that he’s just a genuinely great guy — patient, professional, collaborative, and always willing to go the extra mile. If you’re lucky enough to have David on your team, you can rest easy knowing the job will not only get done — it’ll get done right.

Jorge , 6 lessons with David

Very patient and knowledgeable tutor

Have been working with David for almost half a year and he has always been punctual, easy to work with and always finds a solution for a problem I have. Highly recommend David!

Tetiana, 25 lessons with David

Best Tutor!

David really helped me when I was in a bind studying Python using Jupyter Notebook. He’s incredibly knowledgeable and was able to guide me through the basics, which gave me a strong foundation to build on. From there, we advanced into more complex topics like Folium. Overall, I couldn’t have asked for a better tutor to help me prepare for my college exams.

Saph, 3 lessons with David

Great Teacher!

Professional and knowledgeable about my excel pivot table needs. Took the time to make sure I understood what I was doing and why.

Tiffany, 1 lesson with David

Knowledgeable & easy to work with

David and I had an in person session on excel. He is very knowledgeable and was able to help me as I explained my very complicated request/need on an excel document. He was able to not only Teach me some really helpful formulas, but we were able to solve my problem. I will absolutely be using him going forward and would highly recommend him!

Vanessa, 3 lessons with David

Knowledgeable & easy to work with

David and I had an in person session on excel. He is very knowledgeable and was able to help me as I explained my very complicated request/need on an excel document. He was able to not only Teach me some really helpful formulas, but we were able to solve my problem. I will absolutely be using him going forward and would highly recommend him!

Vanessa, 3 lessons with David

Thank you, David.

David was instrumental in helping me navigate a challenging work project with precision and efficiency. In just one session, I achieved my goal and gained invaluable insights along the way. David’s expertise, patience, and creativity stood out, making the experience not only productive but genuinely enjoyable. The session flew by, and I found myself wishing it could last longer! If only all my teachers had been as engaging and effective as David—I can’t recommend him highly enough!

Kisha, 2 lessons with David

Algebra

David helped my son prepare for a math exam. He's an excellent tutor and we will be back for more help in the tutor. He's patient, funny, and allows the student to explore their own knowledge before giving instruction. My son did great on the exam. Thank you, David!!

Judy, 1 lesson with David