Zipper is a second product from the people who make Forge. You bring it the actual worksheet or problem you are stuck on. It reads the problem, works out which step is going wrong, and if that step depends on an earlier skill you are missing, it teaches the earlier skill first, then returns you to the exact question. It checks you afterwards without help, and again on a later day. It is open now at zipper.vindicaseneca.com, and today it covers one family of algebra: equations with brackets, the multiplication inside them, and the distribution that joins the two.
A student gets 3(x + 4) = 24 wrong and writes 3x + 4 = 24 on the way. Forge would log that as a miss in linear equations and tell you something about how you worked it. Both true, and neither is the thing that needs fixing. The thing that needs fixing is that the 3 only got multiplied into the first term, which is a distribution habit, and the distribution habit often sits on top of a multiplication habit. Explaining the equation again does nothing for that. You have to go back.
That is the whole of Zipper. We look back to move forward.
What it actually does today
- You upload a worksheet or a photo of a printed one, or type the problem. It reads the printed text in your browser; nothing is sent to a reading service.
- You work the problem and paste your steps. Zipper checks each line by calculation, line by line, and finds the first one that stops being equal to the one before. If a line is unreadable it says so. It does not guess.
- If the wrong step is the expansion, it teaches distribution on a different example. If the number work inside that goes wrong, it steps back again to multiplication. Three levels, and it keeps the place it left in each one.
- When you finish an earlier piece, it brings you back to the exact unfinished step of the question above it, with what you had typed still there.
- Then two fresh questions without help, then your original question, then a different whole problem on the same skill. Help you used is recorded as help. A question you have already seen is never reused as a check.
- A day later, a short check on the same skill, kept separate from everything you did on the day.
- You can save to an account and come back, and you get a plain report of what was taught, what you did with help, and what you did alone.
One family of algebra. You announced a product that teaches brackets.
Yes. The route from equations down to multiplication is built end to end and it is the only one that is, so that is what we are shipping. The map of skills behind it is much wider, from counting up through Algebra II, and it has the whole Digital SAT Math and Reading & Writing skill list on it as of this week. A skill being on the map does not mean Zipper can teach it well yet. We would rather say that than let you find out.
Why this belongs next to Forge
Forge and Zipper start from the same idea: the useful information is in the question you missed and why, and the score only summarizes it. Forge finds those misses across a whole test and works each one back with you. Zipper takes one problem you are stuck on right now and changes it.
For the SAT, the overlap is direct. Algebra on the Digital SAT leans on solving linear equations in one variable, and a good share of the misses there are not SAT misses at all; they are middle-school moves that never set. If Forge keeps showing you missing the same kind of algebra question, Zipper is the place to take that question.
The two products now talk, in one direction. When Forge's dashboard tells you what to do next, it can hand Zipper a question you missed: you try it again, read Forge's explanation, answer fresh questions of the same kind with the explanation put away, return to the original, and get a short check three days later. That is Zipper's loop running on Forge's questions. The other half, a Forge miss pointing at the earlier skill Zipper should teach first, needs Forge's math bank tagged to Zipper's skill map, and that tagging is still in progress. We will say so here when it is done rather than before.
State what it does. State what it does not. Do not promise the join before the join exists.
What we are not claiming
We are not claiming that going back and teaching the earlier skill makes students learn faster than explaining the step again. That is the thing Zipper exists to find out, and it has not been measured on students yet. Everything Zipper records is built so that it can be: what was taught, what you answered with help, what you answered alone, and what you could still do a day later. When we have that evidence we will publish it. If it says the detour does not help, we will publish that too.
Zipper also keeps the same rule Forge does on data. Your work stays yours, you can delete it, and nothing about you is sold to anyone.
Stuck on brackets? Bring the worksheet. We will go back as far as it takes and walk you forward again.