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Knowing that this number is a three-digit number from the proposal, let the three-digit number be a (or x, a is greater than 0), and add 1 before this three-digit number to become a four-digit number, which is equivalent to adding 1000 before a, then there is 1000+a=9a, 8a=1000, a=125
Elementary school students should not use the equation much, without the equation solution is like this, 1000 divided by (9-1) to obtain, explanation: since +1 before the original number is 9 times the previous one, then it can be concluded that 1000 plus the original number is nine times the original number, then 1000 is 8 times the original number, you can get the original number is 125
In fact, they are all the same thoughts, and it is recommended that you try to set up unknowns!
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The fourth grade is like this, and now the children are amazing.
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The equations are all above. Here we talk about arithmetic.
That is, the original number is added by 1000, that is, 1000 is 8 times the original number, 1000 8 = 125The original number is 125
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Solution: Let this three-digit number be x
1000+x=9x
8x=1000
x=1000÷8
x=125A: This three-digit number is 125
My comment: As a mathematics problem in the fourth grade of primary school, this problem is indeed a little difficult for children, but after a little brain, I found that he will be very simple. For you, your child, as long as you have the idea of bringing the unknown in your head, coupled with forward thinking, this kind of problem can basically be solved, instead of asking for help on the Internet so much, wasting only your own time.
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Solve the equation and you should be able to do it.
I guess I can understand it in the fourth grade.
Otherwise, you can only use reasoning.
Actually, the truth is pretty much the same.
Solving the equation is.
Let it be xx+1000=9x
If you get 125 reasoning, the last three digits of the number are still the original number, that is, after a number is multiplied by 9, its single digit is still the number.
Exclude 0 (this shouldn't need to be explained).
Only 5 matches between 9.
Keep pushing. If the thousand digit is 1, then the number of the hundred digits cannot be greater than 2
In the case of the 10th place, the 100th place is 1, and the 10th place is 2
So 125 is derived
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Exercise 1
One. Troubles shape a sublime purple robe soaked in the morning glow.
Two. Pulling weeds and fighting hard since it is glorious.
Dial erudition even if the sun shines.
Three. Back and forth, back and back, front and front.
Four. And then in and again in and again in and then
Five. 1.Don't practice at night so as not to interfere with our sleep.
2.Uncle Chen was complimenting him.
3.Uncle Chen has won the award, I won't practice at night in the future, thank you Uncle for reminding me Ah Sui Qinbi.
Exercise 2
One. The fluffy canopy berry is full of plums, and the mangmangs are far away.
Two. Three. A mirror with a layer of cotton.
Four. Access information and learn about the world around you convenientlyUse your own e-mail address to build relationships with children all over the worldOnline shopping, auctions dLearn.
2.Outline. 3.I watched my favorite TV on the Internet, looked up information about studying, and chatted with my relatives on QQ.
Exercise 3
One. The score is extraordinarily hard work, complaining about the flat burden, worrying about grinding ink and electric grinding.
Two. d②x①s②
Three. (1) Tiannan water is beautiful, the spring is fragrant, the sea is fragrant, (2) it continues to be solemn and solemn and intense, and inspires continuously.
Four. Catch the moon'The net is loaded into the net swing that catches the moon.
Catch the moon. The starry sky tonight is so beautiful, and the little stars are twinkling and shining.
But where did the moon go, why didn't she even see a shadow?
I guessed it was I who got him back and made it a beacon for my mom to come home.
I'm going to get it back and make it my favorite desk lamp to accompany me every day in my homework studies.
Exercise 4
One. Basic agility though the destruction ritual is wrong.
Two. Yugong moves mountains - Jingwei.
Reclamation of the sea and plum quenching thirst - painting cakes to satisfy hunger, dogs fighting human power - foxes, fake tigers, good medicine, bitter mouths - loyal words against the ear.
Three. The fireworks in the sky are so gorgeous, so what will the fireworks in the water look like? Seeing this, you must ask, will there be fireworks in the water?
Of course, the aerial fireworks from the water are really unique, the green ones are like lotus leaves in the water, the red ones are like lotus flowers, the purple ones are blooming in the water, and the yellow ones are like fish swimming in the water......With the free flying of fireworks in the empty head, the pictures in the water are more beautiful and more gorgeous than the other.
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