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The average of five numbers is 60. If one of them is changed to 80, the average will be 70. What is the original number?
70 × 5-60 × 5 = 350-300 = 5080-50 = 30
23 times 14 out of 39 plus 14 times 3 is 16 out of 9
The library has purchased 750 literary books and popular science books. It is known that literary books are twice as many as popular science books. How many are literary books and popular science books?
Dear students
There is no one to answer this question, let me answer you. 750 books can be divided into three parts, two are literature books, one is popular science books, (1) literature books have 750 △ 3 × 2 = 250 × 2 = 500; (2) popular science books have 750 △ 3 × 1 = 250, 500 are two times of 250. Are you right? Good health, good bye
Observe the five numbers on the right: 19, 37, 55, a, 91, and deduce a=______ ．
55 + 18 = 73, a = 73
How to calculate 5x-2 = 7x?
Wuwuwuwu, how about 5x-2 = 7x? You can't use the term shifting prawns. Help me
This is very simple
Move 7x to the left of the equal sign 5x-7x = 2
-2x=2
x=-1
How to publish an article in a newspaper?
Is how to contribute to the newspaper
Mail the manuscript directly to the newspaper you want to submit, and mark "submit" on the envelope
If you can, write the name of the column on the envelope
How many jin is a kilogram? How to calculate the algorithm
Simple operation of 1 / 1 × 3 + 1 / 3 × 5 + 1 / 5 × 7 + 1 / 7 × 9 + 1 / 9 × 11 + 1 / 11 × 13
=1/1*3+1/3*5+1/5*7+1/7*9+1/9*11+1/11*13
=1/2*[(1-1/3)+(1/3-1/5)+(1/5-1/7)+(1/7-1/9)+(1/9-1/11)+(1/11-1/13)}
=1/2*[1-1/13]
=6/13
The mathematics interest group held a test. There were 15 questions in the whole paper. It was stipulated that 8 points would be deducted for each right question and 4 points would be deducted for each wrong question. Xiaoying got 72 points in total, and she did it right______ Question
The wrong questions are: (8 × 15-72) △ 8 + 4, = (120-72) △ 12, = 48 △ 12, = 4 (DAO); he did right: 15-4 = 11 (DAO); a: he did right 11 questions. So the answer is: 11
The least natural number of 1 is more than the multiple of 2.3.5
2. The least common multiple of 3 and 5 plus 1
It's three numbers multiplied by one and you get 31
RELATED INFORMATIONS
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