5,3,7 / 3,2,9 / 5,5 / 3, () a calculation problem, find the rule, and work out what number to fill in the brackets

11/7
By converting the above figures, we can get the following results:
5/1、6/2、7/3、8/4、9/5、10/6
That is, the molecules are 5, 6, 7, 8, 9 and 10
The denominators are 1, 2, 3, 4, 5 and 6
The numerator and denominator increase by 1
The numerator is 11 and the denominator is 7, that is 11 / 7

Among the 1000 natural numbers from 1000 to 1999, how many thousands, hundreds, tens and ones are there?

1000 to 1999 are four digit, neat, so there are 1000 thousand digit, 100 digit, ten digit, single digit

Write the numbers 1-1999 from left to right on a piece of paper long enough, with a comma at three intervals. What is the number before 100 commas

100 × 3 = 300, there is a comma every three digits. The 100th comma is in front of the 300th digit
1 × 9 = 9, there are 9 single digits, a total of 9 digits
2 × 90 = 180, there are 90 double digits, a total of 180 digits
300-180-9 = 111, one digit and two digit should be removed, and the comma should be after the 111th digit of three digit
111 △ 3 = 37 111 numbers are 37 three digit numbers. The comma should be after the 37th three digit number
Starting with 100, the 37th number is 136
The number before the 100th comma is 6

1,2,5,13,34, () to find the law

1+1=2
1+2+2=5
1+2+5+5=13
1+2+5+13+13=34
1+2+5+13+34+34=89
So, 89 should be filled in brackets. It's an interesting rule. But if you think about it, you should come up with it soon

Find the rule 1, 2, 5, 13, 34, () how much to fill in brackets

89,5=2×2+1 13=5×2+1+2 34=13×2+1+2+5 89=34×2+1+2+5+13

Find the rule 1 / 2 - 2 / 3 3 / 10 - 4 / 15 5 / 26 - 6 / 35
1/2 ,-2/3 ,3/10 ,-4/15 ,5/26 ,-6/35 ,( ) ,( )

The denominator is 1, 2, 3 n
The molecules are 1 × 1 + 1,2 × 2 - 1,3 × 3 + 1 The (n-1) power of n × n + (- 1)

Use eight numbers of 10, 20, 30... 80 to fill in the small circle and make the sum of five numbers in each big circle
Fill in the small circle with eight numbers of 10, 20, 30, 80, so that the sum of five numbers in each big circle is equal to 210

Put the eight digits of 10.20.30.40.50.60.70.80 in the circle so that the sum of the five numbers on each big circle is 200
There are two groups of five circles in each group, two of which are nested together

80+60+20+(30+10)=200 70+50+40+(30+10)=200

120% of 120 is 24 less than four fifths of a number. What's the number
A number minus the product of 3 / 2 and 2, the difference is 2 / 5, what is the number? (solution of a series of equations)

210 .
120*120%+24=4/5x

Four fifths of a number is more than 20 percent of 120. To find this number, use mathematical formula. Quick

This number = (120 × 20% + 24) △ 4 / 5 = 60

5,3,7 / 3,2,9 / 5,5 / 3, () a calculation problem, find the rule, and work out what number to fill in the brackets