Tokyo Tutor: Starting with My Ex-Girlfriend's Sister

Chapter 19: Keeping Promises

After the two finished dressing and went downstairs, Himeko Kiyoyuki, who was waiting downstairs, was delighted to see her daughter.

"Saki, you have such beautiful clothes."

Mrs. Hime was still immediately struck by her daughter's beauty upon seeing her for the first time today.

"Aoi helped me choose it."

"Aoi, you're very talented. You might become a fashion designer in the future."

"Thank you for the compliment, ma'am."

After the group finished breakfast, Yamazaki Kazuka arrived on time.

"Let's begin today's lesson."

In Himeno Saki's room, the three of them sat around a desk in a very harmonious manner.

Yamazaki Kazuka was unaware of the interaction his two students had engaged in before his arrival.

I just felt that the sun was shining brightly today and everything was calm and peaceful.

A sufficient condition is a condition that provides a sufficient guarantee that an event or proposition is true; that is, if condition A exists, then result B will definitely occur.

In front of the small blackboard, Yamazaki Kazukaze was explaining the most basic mathematics. In his understanding, sets were the simplest and most suitable part of high school mathematics for beginners.

Japanese high schools start in April and finish the first semester of the first year in July. In these short three months, Onari Middle School's teaching progress is not faster than other middle schools; it just has more exams and the exams are more difficult.

Therefore, sets constitute a large portion of the math exam, and are also the easiest part to score points on.

If Himeno Saki can thoroughly understand this part of the knowledge, she can easily pass math.

However, the teaching situation was far more difficult than Yamazaki Kazukazu had imagined. Whenever he started talking about academic topics, Himeno Saki would yawn repeatedly.

"Teacher, I'll go pick a flower."

Himeno Saki blushed and raised her hand.

"Didn't you just go there half an hour ago?"

"I... I drank too much coffee."

The usually carefree Himeno Saki was now acting coy and pleading with Yamazaki Kazukaze through her eyes.

"Go, go."

Himeno Saki rushed outside, while Yamazaki Kazufu sat in a chair and sighed.

"Thank you for your hard work, teacher."

Uesugi Aoi watched the spectacle from the sidelines, not wanting to miss out on the fun.

"It's okay, how's your summer homework going?"

Yamazaki Kazuka looked at the books on Uesugi Aoi's desk.

"Everything is normal at the moment."

"This question is wrong."

Yamazaki Kazukaze spotted the mistake at a glance and, while Himeno Saki was away, explained the problem to Uesugi Aoi.

"I'm back."

When Himeno Saki returned, she looked refreshed and radiant.

Saki-kun, I have a question for you. If condition A guarantees result B, then what is A to B?

Yamazaki Kazukaze decided to ask a pop quiz.

"Um, A is B's... Teacher, I didn't hear the question clearly, could you say it again?"

"If condition A is true, then result B is certain. So, what is A to B?"

Yamazaki Kazufu emphasized every word.

"A is B's..."

Himeno Saki's mind went blank as she looked at Yamazaki Kazukazu with a bewildered expression.

"A is a sufficient condition for B. Saki-kun, didn't I just say that?"

"Yes, teacher, you're right."

Himeno Saki nodded with a silly grin.

"If this sounds abstract, let's put it another way. You need to win the League Challenger Series to have a chance to join a professional team. Winning the Challenger Series is a sufficient condition for you to join a professional team."

"I understand, Mr. Yamazaki."

"Then let's continue, and talk about necessary conditions and sufficient and necessary conditions."

Yamazaki Kazuka felt exhausted. Himeno Saki was too ruthless. In order to get revenge on her mother, she arranged for her to attend Onari Middle School, where she didn't listen to a single lesson.

With only a week to spare, is it really enough time? Yamazaki Kazuka felt incredibly exhausted.

"get out of class dismissed. I'll assign you homework this afternoon. It'll be all from this morning's lessons, nothing too difficult. It's at the level of a regular high school student."

After covering all the math, physics, and chemistry lessons, Yamazaki Kazukazu announced the end of get out of class. Fortunately, the teaching progress was still within his plan; however, how much Himeno Saki had absorbed could only be determined by the quiz this afternoon.

The three of them went downstairs for lunch and a nap.

"Thank you for your hard work, Yamazaki-sensei. Is Saki paying attention in class?"

"Saki is very disciplined in class."

"That's great. In the past, Saki's lessons drove many tutors crazy. One tutor said, 'Your daughter is like a monkey from the African jungle.'"

"Mom, please stop talking."

Himeno Saki complained, her face flushed.

Yamazaki Kazuka was relieved that he had established a good relationship with Himeno Saki before classes officially started. In his presence, she only went to the restroom a few times and spaced out during class.

"Mr. Yamazaki, I have to go out of town the day after tomorrow. I'm leaving my Saki in your care."

"Mrs. Himeno, are you going away for a few days?"

"Three days. This time it's a tea ceremony competition being held in Kyoto. As a judge, I need to go there."

"I understand. Don't worry about Saki-san, leave her to me."

Hearing this, Uesugi Aoi was overjoyed. This would allow Himeno Saki to wear even more revealing clothes. Then, she could find an excuse to leave for a morning, and the miniature camera might be able to capture some forbidden scenes.

After lunch, Yamazaki Kazuka found Aunt Uesugi.

I keep my word. Since I promised Uesugi Aoi yesterday that I would help her get her game console back today, I will definitely do it.

"Aunt Uesugi, there's something I'd like to ask you."

"What is it, Mr. Yamazaki? Just tell me."

"Could we return Aoi's game console to her?"

"Oh? Aoi told you about this."

"Well, since it's summer vacation, let's give Aoi more time to play games."

"But Aoi has been playing games with Sakura-san for so long..."

"She doesn't really like that game; she only plays it to fulfill Mrs. Himeno's request. Let's give Aoi her game console back and cheer her up."

"Oh, Mr. Yamazaki, you don't know this. Don't think that Aoi is very well-behaved. In fact, she has very poor self-control."

"I'm worried that if I give her the game console, she'll play games day and night."

"Before, when she was at home, her parents kept an eye on her. Now, if we put the game console in her room, I'm worried..."

"Don't worry, leave this to me. I'll keep an eye on Aoi."

"Really? Then I'll leave it to you. I'll have her father bring the game console over this evening."

"Actually, I really don't want her to play video games; that's something boys play."

Aunt Uesugi always feels that her granddaughter has a boyish personality. Will a man really want a woman like that in the future?

"This preference is not limited to either men or women."

"Really? I've always hoped that Aoi would marry a good husband in the future, like Mrs. Himeno. Won't her preferences be a disadvantage?"

"No, maybe in the future I'll find common ground with a young master who likes playing games."

"Haha. Thanks for your kind words, Mr. Yamazaki."

Aunt Uesugi didn't believe it, but she still agreed to Yamazaki Kazukaze's suggestion.