Tian Xinmiao found an extended lamp rope on the wall next to the kang, pulled it down, and with a click, the lamp that fell on the edge of the kang turned on.

Judging from the brightness, the lights in Ruan Haoyan's house should be about forty watts, and the light in the house is much stronger than that in their hut.

Tian Xinmiao looked at the book, perhaps accustomed to reading under the white light, in this dim light, although the words can be seen clearly, but the dim yellow makes people feel extremely uncomfortable, if you read for a long time, it will not be good for the eyes.

Tian Xinmiao's brows furrowed slightly, and all kinds of table lamps flashed in front of him.

But when she remembered what era and where this was, she couldn't help but smile self-deprecatingly, it seemed that she hadn't figured out that she was no longer the same person.

Seeing Tian Xinmiao turn on the light, Ruan Haoyan smiled at her, "Sister-in-law, let's go to the kang!" ”

Tian Xinmiao just collected his thoughts, stared at the question in the book, and when he heard Ruan Haoyan's words, he couldn't react for a while.

Looking at Tian Xinmiao, who was a little stunned, Ruan Haoyan pulled her arm, "Let's lie on our stomach, can you give me a lecture?" ”

"Okay, let's go to the kang." Tian Xinmiao, who finally reacted, hurriedly responded, and quickly glanced at the furnishings in the room again.

In addition to the kang and the two small boxes on the kang, there was a small low table in the bottom of the house, the square stool she had sat on when she helped Ruan Haoyan comb her hair, and then the corner cabinet in the corner.

It is said to be a corner cabinet, that is, a simple shelf, the upper two floors are grille-shaped, the top is placed with a toothbrush jar, in the middle are three or four third- and fourth-grade Chinese and mathematics books, and there is a small door on the bottom floor.

Tian Xinmiao instantly understood why Ruan Haoyan asked her to go to the kang with her, because on weekdays, Ruan Haoyan must be the same as when she was a child, lying on the kang to do her homework.

Tian Xinmiao followed Ruan Haoyan to the kang and climbed to her side.

She temporarily suppressed the calculation in her mind and set her eyes on the question.

The problem is a practical problem, and at a glance, it can be easily solved by using a system of binary equations.

Before the topic, Tian Xinmiao's heart suddenly moved, and he spoke: "Haoyan, have you ever studied the binary system of equations?" ”

"Binary Linear Equations?" Ruan Haoyan thought about it, and didn't seem to have heard this term, so she shook her head, "Sister-in-law, we haven't learned it." ”

Tian Xinmiao secretly praised his wit, and hurriedly flipped through the math book forward, only to understand that this part of Ruan Haoyan was learning was just coming into contact with equations, that is, he could only assume an unknown number, establish an equation, and then solve it.

Tian Xinmiao put his eyes on the problem again, looked at it carefully, and then simply wrote on the back of the used paper in the old book handed over by Ruan Haoyan, and then figured out the process of solving the problem.

However, she did not tell Ruan Haoyan the process of solving, but guided her step by step from how to assume unknowns, how to build equations, and finally solve equations.

"Look, do you know how to solve this problem yourself?" When Ruan Haoyan solved the problem, Tian Xinmiao joked with a smile.

Ruan Haoyan was a little excited because of the successful solution of the question, "It turns out that this question is so simple, I didn't think about it carefully enough." ”

"Therefore, when we see the problem in the future, we must first take a closer look at the known conditions, what is the relationship between these conditions and the answer to the required solution, and if not, what conditions can we use to establish a relationship between them."

"Uh-huh, sister-in-law, I see."

Ruan Haoyan happily turned to the next question, "Sister-in-law, I'll take a look at this question first, I really can't solve it, you can tell me about it." ”