01 / MOVE ON
After grading and reading the explanation, do you move straight on?
It makes sense while you read it. Then a similar problem stops you in the same place.
111sm · POWERED BY FULLMO
Maths. Solve. Review.
Stop losing marks on solved problems. Choose a paper or topic, practise at your own pace, and review with hints and explanations.
Built by
TRINITY MATHSLAB / Sungmin Kim, mathematics teacher. We build a mathematics training app for high school students.
- Public beta · free to start
- In the browser, or the iPhone, iPad and Android apps
- No sign-in, no name, school, or phone number
- Sign in for handwriting grading, the helper and account records
Signed-in demonstration, 19 September 2026: the app extracts 6 from handwritten a+b=6. We confirm it without editing, then mark and save the work. Marking compares the confirmed final value with the answer key. Demonstration handwriting, with the wait for reading cut and the mobile version cropped from the left column of the same desktop screen.
Open video file ↗02 / WHY AGAIN
There is a reason the same problem comes back wrong, no matter how much you solve.
Solve, grade, read the explanation, move on. In that routine, neither the reason for the mistake nor the way you worked reaches the next session. The reason stays in your head, and a few days later a similar problem stops you in the same place.
02 / NO RETRY
Do you write mistakes down, then never find time to solve them again?
The mistakes are filed away. New problems keep coming, and the retry keeps getting postponed.
03 / STILL VAGUE
Solving a lot, but still unsure where you are weak?
You see the score and the number wrong. Which unit keeps producing the same mistake is easy to miss.
Mathematical skill is not only how many problems you solve. It changes with what you record after a mistake and how you train it again.
Where do you want to start?
Two minutes to read
Getting started
Four steps to a first paper, three things to check before you begin, and what gets saved.
5 questions · about 30 seconds · nothing is stored
Study habit check
Answer five questions and get what to look at first, whether linking concepts, pacing or reviewing mistakes, plus a practice for this week.
03 / HOW IT WORKS
Pick a question, solve it, and try again with a hint.
What a student does in the app, in order. Every screen is the real 111sm.app, captured without signing in, with the date it was taken.
01 / TODAYNo sign-in Start from the Today tab
The app opens on the Today tab with today's mini: a few past mock-exam questions, easiest first. Press Start; no sign-in is needed.
Real 111sm.app screen / Captured 2026-10-19The Today tab. Today's mini comes first, and the tabs lead to Study, Community and My record. 02 / PAPERSNo sign-in Choose a past paper in the Study tab
In the Study tab, past papers are chosen by year group, year and sitting. Take the whole paper at once as in the exam, or mark one question at a time. Topic practice works by course and unit.
Real 111sm.app screen / Captured 2026-10-19Choosing a past paper. Pick the curriculum, the year group, the school year and the sitting, then a whole paper at once or one question at a time. 03 / SOLVENo sign-in Work it out on the working paper
Work it out by hand on the working paper, then choose an answer. The working paper needs no sign-in. Marking from the answer read in your handwriting needs a sign-in, with a daily limit on free accounts.
Real 111sm.app screen / Captured 2026-10-19The practice screen. The exponents are added by hand on the working paper before choosing an answer. Demonstration handwriting. 04 / HINTNo sign-in Missed it? Try again with a hint
When you mark one question at a time, a wrong answer lets you read a hint and try again before seeing the answer. The hint is a nudge, not the solution. Marking the second try leaves your first answer and first mark unchanged.
Real 111sm.app screen / Captured 2026-10-19The hint after a miss. It points to the shared base and the sum of the exponents; the answer and the explanation can be opened after. 05 / EXPLANATIONNo sign-in Solve it again, then read the explanation
Get it right on the second try and the answer and explanation open; if you are stuck, you can open them straight away. Under the explanation, you can send the question to the teacher. After sign-in, you can also talk it through with the helper, which asks questions instead of giving answers.
Real 111sm.app screen / Captured 2026-10-19After the second try. The first answer stays on record, and the answer and the explanation open. 06 / REVIEWNo sign-in Missed topics come back to Today
A topic you miss in today's mini comes back on the Today tab as a weak-spot check, with a different question from the same topic. This review record stays on the device.
Real 111sm.app screen / Captured 2026-10-19The Today tab after two misses in today's mini. It suggests checking the topic again with a different question.
NEXT STUDY
Three moments, one change each.
For each moment, one thing to change and the place in 111sm where you can do it.
01
After you close the explanation
If this is you
The explanation made sense as you read it, but the next day you can't see where to begin.
Try this
When an answer is wrong, read the hint before the explanation and try once more. If you have read the explanation, put it away and write the solution yourself from the start.
In 111sm
Mark one question at a time, and a wrong answer lets you try again with a hint first. Your first answer and first mark stay as they were.
02
When you start the next session
If this is you
Yesterday's mistakes are still there, and today you start on new questions anyway.
Try this
Take today's first question from the topic that stopped you yesterday. New questions come after you have redone it.
In 111sm
A topic you miss in today's mini comes back on the Today tab as a weak-spot check, with a different question from the same topic. This review record stays on the device.
03
Before you move past a right answer
If this is you
The answer is right, so you go straight to the next question.
Try this
Read one other solution, even to a question you got right. Then solve it again, starting from the condition that solution used first.
In 111sm
Under a marked question, open the other solutions to read any that students and teachers have posted for it.
04 / FAQ
Questions before you start
Open a question to read the answer.
01Who is it for?
High school students who solve maths problems regularly but keep missing similar ones. Especially those who never managed to sort out their weak types, or who keep a mistake notebook they never solve again.
02What problems are in it?
Published past maths exam questions from the national exam and mock exams, selectable by paper, unit, or question number. Hints and explanations come with them, and more past papers keep being added.
03Which devices does it run on?
It runs in the browser with nothing to install, and you can also install the app from the App Store on iPhone and iPad or from Google Play on Android. It is built for a tablet in landscape, and works on a phone or laptop for solving and reading your record. Handwriting on the question is most comfortable with a tablet and pen.
04Does it cost anything?
Solving, hints and explanations, mistake review and reading the question rooms are free. Handwriting grading and helper conversations have a daily limit on free accounts. Care, where the teacher and an assistant read and comment on your handwriting and mistakes, is a paid monthly subscription; the price and how to apply are shown on the app's account screen. Questions are welcome through the trial enquiry on this page.
05Does the helper give the answer?
No. The helper asks questions so you think again, and it never judges whether your working is right. Its replies are generated by a program, not a person, so they can be wrong; when something looks off, check the explanation. Conversations are not stored.
06Where does my record live?
Answers in progress and time spent may stay temporarily in this browser. After a full paper, you choose whether to save its result to an account; some unit and question drills do not save paper results. Handwriting is saved separately when you confirm and submit the answer after sign-in. Unsaved writing can disappear when you change questions or refresh.
07What does handwriting grading check?
It reads your handwriting and suggests an answer. You confirm or correct the value before submitting it for comparison with the answer key. It does not check every step of your reasoning. If the writing is unclear or the format is unsupported, check the value yourself before submitting.
08What does signing up require?
You sign in with a Kakao, Google or Apple account, confirm that you are 14 or older, and agree to the privacy policy. No name, school, phone number, or date of birth is collected.
09What should parents look at together with the student?
Ask not only how many were right, but where the student got stuck and whether the second attempt was solved alone. Choosing one or two questions to solve again next time also helps. Care, where the teacher and an assistant comment directly, is a paid monthly subscription that a parent applies for, explained on the app's account screen. Questions are welcome on KakaoTalk or by email.
10How can I ask about a consultation or trial?
Send an enquiry through 1:1 chat on our KakaoTalk channel. You can decide after discussing the format and schedule in the reply. Email is also available.
TRINITY MATHSLAB
The app and the books, the concept map and the teaching.
111sm is our main high-school maths service, and Trinity Press is how we make our textbooks and lesson materials. Concept exploration and the founder’s teaching and writing each serve a distinct need beside them.
Main service · High-school maths in Korea
111sm
High-school maths, from practice to review. Choose a paper or topic and practise one question at a time or as a full paper, without signing in.
Explore maths practiceProduction · Textbooks and lesson materials
Trinity Press
Our production system makes the printed textbooks and the lesson board slides from one manuscript. No question is typeset twice, and a correction made in the manuscript reaches both the book and the slides.
Complementary · Concept exploration
maths.study
Explore concepts through a 3D world or a 2D map, answer questions and find a route for your next study session.
Explore the concept mapFounder · Teaching and writing
mathskim
Sungmin Kim’s personal brand. Two free books and a maths question channel introduce the thinking behind the teaching.
Meet the teacher and author05 / START
Start solving, or ask about a guided trial.
START NOW
If you want to start right now
Explore papers and topics, then practise without signing in. Sign in to save results or request handwriting grading.
Get the iPhone and iPad app on the App Store Get the Android app on Google Play
Today's study isn't done when you have read the explanation. It is done when you have solved the question again without it.
Explore maths practice 1일 1실모 / powered by FULLMO / Public beta · FreeGetting started →GUIDED TRIAL
If you would like guidance
Get in touch through the Trinity MathsLab KakaoTalk channel. Discuss the available options and schedule in the reply.
Ask about a trial on KakaoTalk →Open the channel, choose 1:1 chat, and send your enquiry. Arrange a time after receiving a reply.You can also get in touch by email.sungmin.t@maths.study