1/21+5/8+4/9+3/7=

RELATED INFORMATIONS

• 1. When a () is multiplied by a, the product is greater than 5 / 9; when a () is multiplied by a, the product is less than 5 / 9 In addition, the side length of a square is one fourth of a meter, its perimeter is () meters, and its area is () square meters. Why?
• 2. What's the total number of 0-9 permutations in a group of four, the most complete answer, thank you!
• 3. Take any 4 digits from 0 to 9 to form a 5-digit permutation The number permutation and combination problem of 0-9 Any four of the ten digits from 0 to 9 make up five digits. 0 can be placed in the first place. The first three digits must not be the same, and the last two digits can repeat at most one digit with the first three digits. How many digits are there, Any four of the ten digits 0-9 make up five digits. 0 can be put in the first place. The first three digits can't be the same. The last two digits can repeat only one digit and the last two digits can be the same. How many permutations are there
• 4. The permutation and combination of four numbers 1234 is composed of: one two three four twelve thirteen fourteen twenty-three twenty-four thirty-four one hundred and twenty-three . How many combinations are there? And how are they calculated? There is no requirement for the order of arrangement
• 5. Natural numbers 1, 2, 3 In the order of 123456 910112… If it reaches 2889 digits, the sum of all digits
• 6. Two similar permutation and combination questions, in 1.2.3.4 these four numbers constitute three digits without repeating numbers, in which the odd number has 2. Take any three digits from the six numbers 0-5 to make up the unrepeated number, of which the even number is Please let me know by permutation,
• 7. In the number 1-33, randomly choose 6 digits so that the sum of 6 is 100. How many choices are there? What is the formula? Is this a permutation?
• 8. How many of the five numbers are multiples of 4? (permutation and combination) Please explain how to do it
• 9. The six numbers from 0 to 5 make up four digits, which can be divided by 25. How many such numbers are there without repetition
• 10. The permutation and combination are composed of numbers 1.2.3.4.5. How many of the three digits without repetition can be divided by 9
• 11. (- 1 / 63) / (1 / 9-2 / 7 + 2 / 3-4 / 21)=
• 12. 987 × 655-321 of 666 + 987x654 is calculated
• 13. 32.9 - (14.2 + 7.1) - 4.2 with the simplest method
• 14. 23+22+21+… +1+0+1+2+3+… +54 = how much did you get in the end?
• 15. 2.5*0.4+0.21*3
• 16. 5 / 6 + 5 and 1 / 5 + 1 / 6 + 5.8
• 17. 759 * 11-759 321 * 77-62 * 321 26 * 145-44 * 26-26 15 * (40-6) 27 * 31 + 31 * 72 + 31 How to calculate easily? It must be easy to calculate!
• 18. A and B are coprime, and their greatest common divisor is? And their least common multiple is?
• 19. Two coprime numbers whose greatest common divisor is 1 and least common multiple is () Large numbers are multiples of decimals, their greatest common divisor is (), and their least common multiple is ()
• 20. 36 may be the least common multiple of those two numbers? Write four YES