Choose a unit
Pick a semester unit or comprehensive review for grades 1–6, then choose a difficulty level.
How it works
Choose, write, and try again
Work it out by hand
Use the scratch space for your working, then write your answer. A number keypad is available when handwriting recognition is difficult.
Review and retry
Revisit missed questions in the review notebook and check your practice days in the calendar and learning history.
Features
Made for everyday math practice
Handwriting recognition
Write digits and symbols in the answer box. You can select a recognition candidate or use the number keypad.
Grade-level practice
Practice calculation-focused units from Korean elementary grades 1–6 by semester, then try comprehensive review.
Step-by-step hints
Get guidance when you're stuck. Watching an ad may be required for additional hints.
Review notebook
Collect missed questions and solve them again. Correctly answered questions leave the review list.
Learning history
See practice days in a calendar and inspect session results and individual answers.
Jellies and customization
Earn jellies through practice and use them to personalize ink colors, pens, and your scratch space.
App preview
See the app in action
Start learning
Start with one problem today
Sem OneStep is available on Android. App content is in Korean.
Policies
Policy documents
Contact email
official@yenalab.com
Example topics
Login issues, data recovery, account deletion, ad rewards, learning record sync