Keywords: Magician Evil Primary School Grade Five

This article is suitable for: the fifth grade of primary school.

Composition source:

This 400-word composition is about the fifth grade of primary school. The topic is: Mysterious Mathematics Valley (IX)-Evil Black Magician. Welcome to contribute.

The mysterious valley of mathematics (9)

Evil dark wizard.

Meimei glared at Peter and whispered to him, "Look at you, Peter, this question is so difficult that I have no idea at all." Who told you to agree to the lion's request from the beginning, and now we have something big? "

Bite open his hand and say helplessly, "I can't help it." Those two lions were terrible just now, I have to agree! " "

Lily crossed her waist and said to Meimei and Peter, "Let's stop complaining about each other. Let's find a way to help them calculate their age! " "

Rhubarb and yellow lion opened their eyes wide and stared at them angrily, as if to eat them.

Hearing Lili's words, the anger on the faces of rhubarb and yellow lion disappeared by half, and they all said in unison, "How to calculate? Tell us quickly! "

Lily said slowly, "To know your age, you must first make an equation."

"What, what equation is delicious?" Rhubarb asked impatiently.

"The equation is not something to eat, but an unknown equation. Let's set the required age as an unknown X, and then bring X into the equation to find out your age. " Lili patiently explained.

"Wow, this equation is amazing! Tell us how to do the equation! " The yellow lion pleaded.

"We assume that the age of the yellow lion is X this year, and the age of the rhubarb is (X+ 10). Four years ago, the age of yellow lion was (X-4), and the age of rhubarb was (X+ 10-4). Because rhubarb was twice the age of yellow lion four years ago, we can make an equation. Lily listed the equations on the ground as she spoke.

Meimei patted her head and suddenly realized, "I'll solve the equation." Then she began to solve the equation step by step.

2(X-4)= X+ 10-4

2X-8=X+6

2X- X=8+6

X= 14

Looking at the beautiful answer, Peter said to rhubarb and yellow lion, "Yellow lion, you are 14 years old this year, rhubarb, you are 10+ 14=24 years old this year!"

The yellow lion and rhubarb are smiling. They said gratefully to Mei Mei, Lily and Peter, "Wow, you are so smart! Thank you! "

Meimei, Lily and Bit are very proud. They waved to rhubarb and yellow lion and walked on.

I don't know when the rain stopped and the sky was bluer than before. Grandpa Sun is lying leisurely in the sky. Clouds like "cotton candy" are floating around. At the end of the day, a beautiful rainbow bridge appeared. The bright colors of the rainbow add a little vitality to the sky.

Just as they were intoxicated with this infinite beauty, they heard a bang. Two magicians in black robes appeared in front of them. A magician's robe says: Botin, and another magician's robe says: Apollo.

The magician named Botin said viciously, "The maze is the home of our black magician. How dare you break into our house? You are responsible for this mistake you made! " "

"Yes!" Apollo chimed in.

Mei Mei, Lily and Peter looked at each other.

"So! We won't embarrass you, as long as you can help us solve a difficult problem and let you live! " Botin said with a bad smile.

"Great, helping others solve problems is our strength!" Peter is a little gloating.

"This question is very difficult. The ten-eyed devil asked me to go to the magic bridge with Bertan to cast spells. As long as we are on the magic bridge, we can make this magic work anywhere. I set out from the west of the maze, and Botin set out from the east of the maze. The west is 3000 meters away from the magic bridge, and the east is 5400 meters away from the magic bridge, with a length of 600 meters. I walk 10 kilometers per hour, so how many kilometers or more do you think Botin has to walk every hour to meet me on the bridge? " Apollo finished the problem in one breath.

Can Mei Mei, Lily and Peter solve this problem again and move on smoothly?

(unfinished, to be continued)