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freepracticeSAT.com vs 1600.io: Video Explanations or a Diagnosis?

By Dr. Daniel Brink, Ph.D. in Mathematics Education, 32 years teaching math · October 28, 2026

Students who are serious about SAT math often find 1600.io on Reddit. It is best known for video explanations of the official practice tests: you miss a question, you watch someone solve it. I think that is a good thing to have. It is also a different job from the one my site does, and the difference is worth understanding.

Full disclosure: I built freepracticeSAT.com. The 1600.io details come from their website, checked on October 28, 2026.

What 1600.io offers

1600.io sells a membership at \$6.99 a week, \$19.99 a month or \$99.99 a year. According to their site, it includes:

• more than 6,000 video explanations of questions from released SATs, including the official digital practice tests, for every section,
• Desmos solutions for many of the math questions, and a course on using Desmos on the digital SAT,
• an online math course (their "Orange Book") with about 1,000 example and practice problems,
• live classes and recordings of past classes.

Watching a solution and knowing your mistake are not the same

Here is a small example of what I mean. Say a question asks:

A video explanation shows the correct steps: divide both sides by $2$ to get $x-3=5$, then add $3$. The student watches, nods, and moves on. That is useful.

But the wrong answer $\frac{13}{2}$ tells me more than "wrong." It comes from writing $2x-3=10$, which means the student multiplied the $2$ by the $x$ and forgot to multiply it by the $3$. If that student makes the same slip on three other questions in the test, in three different topics, the real problem is not any one of those topics. It is distributing.

That is what my site looks for. Every wrong answer choice in my 4,700 questions is tied to the mistake that produces it, and every question is tied to the basic skills underneath it, the 280 skills I call the DNA of SAT math questions. After a test, you see which mistakes and which basics keep coming up.

How they compare

Where 1600.io is the better choice

• You are working through the official College Board tests and want to see every question solved.
• You learn well by watching someone work.
• You want help with reading and writing too.

Where my site is the better choice

• You have used up the official tests and need more full-length math practice.
• Your score has stopped moving and you don't know why.
• You want practice at your level: easy, medium, hard or mixed.
• You would rather not pay for anything until you know what your problem is.

How I tell students to review a missed question

Whichever site you use, the review is where the points come from. When I go over a test with a student, we sort every missed question into one of three piles before anyone watches a video:

1. I knew how, but slipped. A sign error, a misread question, a number copied wrong. The fix is working on paper and checking, not more lessons.
2. I didn't know how. The student has never really learned this skill. A video or a lesson helps here, followed by a few more questions of the same kind.
3. I ran out of time. The student could do it, but not fast enough. The fix is practice under time, and knowing when Desmos is quicker than algebra.

Only the second pile is really about watching someone solve the question. Students who skip the sorting tend to watch a lot of videos and keep making the same slips. When you take a test on my site, the results are set up to help with this sorting: the mistakes it names are mostly of the first kind, and the basic skills it points to are mostly of the second.

A word on Desmos

Both sites take Desmos seriously, and so do I. The graphing calculator is built into the digital SAT, and for many questions it is faster than algebra: graph both sides of an equation and read off where they cross. 1600.io has a full course on it. On my site, the Desmos video walkthroughs are part of the \$29 plan, and the free article on how to use Desmos on the SAT covers the three methods I use most.

Using both

They fit together well. Take a full math test on my site and look at which mistakes come up. When you work through an official test in Bluebook, use 1600.io's videos to see how the questions you missed should be solved. Then go back to my site and take another test to check whether those mistakes are going away.