Numbers up to 5 in 1st level
Numbers up to 9 in 2nd row
What number is 3rd stage?
The order of the four numbers
5th level 1 large number and 1 small number
6th gear 0
Size comparison of 7-stage numbers
8th level fun way to solidify concepts
Collecting and teaching numbers up to 9th Dan 5th Dan
Collecting and teaching numbers up to 9 in the 10th level
Adding numbers up to 9 in 11th row
Addition of numbers up to 9 in 12 steps
Subtract numbers up to 9 in 13th row
Subtraction of numbers up to 9 in 14 levels
15th level 0 addition/subtraction
Addition and subtraction of numbers up to 9 in 16 stages
17th floor, exciting concept development
18th floor 10th floor
19th floor, 10th floor
Collecting and teaching 20 levels
21 Fun Concept Building
Count by grouping 22 groups of 10
Numbers up to 23 and 50
The order of the 24 numbers
Size comparison of 25-stage numbers
26. Confidently solidify your concepts
27-stage number concept summary (1)
28-stage number concept summary (2)
29. Develop your critical thinking skills
30 Steps to Developing Creativity

■ A solid math book built on five clear principles

The subject that our children are most insecure about and the subject that parents worry about the most is, as you might expect, math.
Teacher Ha Yu-jeong has received countless requests for math study methods and math textbook recommendations at both the actual school and the online school, Anywhere School, and has long been concerned about the anxiety children and parents feel about math and the importance of starting math studies.
So, I put all my 18 years of teaching experience into one book, “First Grade Math: Complete in 30 Days.”

The author says that whenever there were requests for math textbooks and learning methods, he provided help tailored to the children's characteristics. However, this was only possible after the children had developed a certain level of study habits, and he always felt regretful about the lack of textbooks suitable for children who were just taking their first steps.
So, to fill that void, I established five clear writing principles and published “First Grade Math.”
The writing principles are as follows:


① Contains various training exercises for counting numbers
② Focus on conceptual problems rather than drill-type problems.
③ It will enhance the transferability of the sense of numbers.
④ Include sufficient open-ended tasks.
⑤ Utilize cognitive resources that assist in learning operations.

This book is designed to incorporate clear principles into learning elements, making it a perfect warm-up for children just beginning to study math.

■ A mathematics textbook and study guidebook

In the beginning of this book, there are six “correct methods for studying math for the first time.”
Before beginning the study, parents should fully understand the study method and help their children apply it to this book and all their math studies.
The effects of study methods may not be immediately visible, but math is a cumulative subject, so the effects will gradually become apparent as you advance through the grades.
Conceptual learning and emotional management must be done simultaneously so that children feel positive emotions like, "Math is doable?" or "I was so scared in the first place," and do not give up on the marathon that is math.

■ Learning numbers and basic operations up to 50, reflecting the revised curriculum

The 2022 revised mathematics curriculum is characterized by transferability and self-directed learning.
We encourage you to understand the concepts clearly, utilize and apply them, and develop your own solution.
This is also directly related to self-directed learning.
This book is divided into the following sections: “Concept Building,” “Yahoo Play Time!”, “Summary of Number Concepts,” and “Developing Thinking Skills.”
We've included plenty of pages so you can fully review and apply what you've learned.
Use this page to help children recognize their own shortcomings and become self-directed in their studies.


This book consists of “Numbers up to 50,” “Number Operations up to 9,” and “Collecting and Teaching Numbers Under 20,” which are covered in the “Numbers and Operations” section of the first semester textbook for the first grade.
80% of elementary math is numbers and operations.
In other words, the beginning of mathematics is numbers and operations.
We hope that you will start studying math with energy by learning numbers up to 50 and basic operations using Teacher Ha Yu-jeong's unique method of studying math.