△=( ) ○=( )
2. Xiaoqing put 1, 2, 3, 4, ... 97, 98, 99, 100,10/together and arranged them in multi-digit order,123456 ...
3. There is a column number, which is arranged in a certain order: 1, 4, 7, 10, 13, 16, 19, 22, 25, ... So what is the 99th number on the left?
4.3000 minus 285, plus 282, minus 285, plus 282, ... According to this calculation, how many times will the result be 0?
5. Square vegetable field with side length12m. If we want to double its area, how many meters will it add on one side and on the other? (writing process)
1. Some people work continuously for 24 days, earning 190 yuan (daily wage 10 yuan, working part-time on Saturdays and having a rest on Sundays, without pay). It is known that he started work on a day 1 in late June, and this month's June 1 happens to be a rest day. Q: What is the date on February when this person finished his work?
2. If the eight numbers 1, 2, 3, 4, 5, 6, 7, and 8 are respectively filled in the following formulas (there are no identical ones), then the formula with the smallest difference is □□□□□□□□ -□□□□□.
Four cars transport 30 tons of cement every day. How many days does eight cars transport 120 tons of cement?
4. Six people in the road repair team will repair a section of road in 45 days. How many days will it take if nine people are added?
1, Xiao Gang weighs 40kg, Xiao Lin weighs 42kg, Xiao Li weighs 38kg and Jun Xiao weighs 52kg. So what is their average weight?
2. The average score of three math exams in winter and winter is 89, and the average score of four math exams is 90. What was the score of the fourth math exam?
3. The fruit company brought in 83 baskets of apples, 74 baskets of peaches, 64 baskets of strawberries and 7 1 basket of pears. Finally, the number of baskets of oranges was 32 more than the average number of baskets of five kinds of fruits. How many baskets of oranges did the fruit company bring?
In a physical examination, the average weight of Xiaohong, Xiao Qiang and Xiaolin is 42kg. The average weight of Xiaohong and Xiao Qiang is 6 kilograms heavier than that of Xiaolin. What's Xiao Lin's weight?
If you want to have the magical ability to decipher passwords like Sherlock Holmes, you must not only have extraordinary reasoning ability, but also know a lot of other knowledge. However, as long as you have the heart, you can crack some simple passwords.
Now let's look at an example:
It is said that when British physicist Newton (1642- 1727) was young, his academic performance was almost the lowest in the whole school. Later he made up his mind to change this depressing situation. Once, he did his homework neatly without any mistakes, but just as he put away his pen and notebook, something terrible happened: ink spilled, leaving ink on one of his arithmetic problems. The figure below shows this unpleasant result.
Only three figures in the formula are clear. Newton tried his best, and finally remembered that the whole problem just used the numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, all 10, the same one.
If this is a password consisting of 10 numbers from 0 to 9, can you decipher which numbers are covered by ink?
Because there are 10 numbers covered by ink, the original formula should be:
2 8 ?
+? ? four
────—
We can write this formula as follows:
28A
+CB4
────—
GFED
Each English letter represents one of the numbers 0, 1, 3, 5, 6, 7 and 9 respectively.
Let's consider thousands of g's first. Two three-digit numbers add up, and the sum is four digits. Because the numbers on the two hundred digits add up, the sum on the thousand digits is 1, so G can only be 1. At this point, the formula becomes:
28A
+CB4
────
1 Federal Reserve
Look at the c and f in a hundred miles. If you want to ensure that 1 can be entered into thousands, C cannot be less than 7, that is, C can only be one of 7 or 9.
Let C=9, then if the ten digits are not rounded to hundreds, f =1; If the decimal places are rounded to hundreds, F=2. This is a repetition of the known pattern. So C≠9.
So C=7 and F=0. that is
28A
+7B4
────
10ED
At this time, b may be one of 3, 5, 6 and 7.
If B=3, then there should be E= 1 or 2, but this is impossible;
If B=5, then E=3, but 6+4≠9, 9+4 ≠ 6;
If B=6, then E=5, then let A=9, then there is D=3.
Tidy up:
A=9，B=6，C=7，D=3，E=5，F=0，G= 1 .
So, Newton's formula should be:
289
+764
────
1053
1、、△+○=9 △+△+○+○+○=25
△=( 2 ) ○=( 7 )
2. One digit: 9 digits -9 digits
Two digits: 90 digits-180 digits.
Three digits: 2-6 digits
A * * *: 9+ 180+6 = 195 digits.
3, a * * * needs to add (99- 1) 3, which is 294, and add the first item 1, then the 99th item is 295.
Subtract 285 for the last time, and the rest will add 282 after each subtraction, so you actually only subtract 3.
3000-285=27 15
27 15 ÷ (285-282) = 905 (times)
905+ 1 = 906 (times)
5. Original area: 12× 12 = 144 (square meter)
Existing area: 144× 2 = 288 (m2)
Now the other side: 288÷ (12+4) = 18 (m)
Compared with the original: 18- 12 = 6 (m)
This problem does not need to be mastered by children. (This area has not been studied)