Number reasoning 1,1,8,16,7,21,4,16,2. () what's the next number?

Number reasoning 1,1,8,16,7,21,4,16,2. () what's the next number?

ten
The last number is 1, 2, 3 and 4 times of the previous number, so the last one should be 5 times of 2

1: 21, 33, 35, 38, () 2:0, 1, 1, 4, () number reasoning,

The first one: the answer should be the product of two prime numbers. The first one is the product of prime numbers: 3 * 7 = 21, 3 * 11 = 33, 5 * 7 = 35, 2 * 19 = 38
Second: equal to 19, the square of the third term = the square of the second term + 3 * the first term

Numerical reasoning 8, - 4,2, - 1,1 / 21,3 / 4,9 / 5,7 / 16,25 / 9, () solving problems
A 15/38 B 11/36 C 14/27 D18/29

-100/12.5 ,80/-20 ,-40/-20 ,20/-20,1/21 ,3/4,9/5,7/16,25/9,15/38
Choose B

Number reasoning 1,2,2,3,8 / 3 ()

1,2,2,3,8 / 3, () are multiplied by each other to obtain:
2 4 6 8 （10）
The answer is 30 / 8, which is 15 / 4

The number of chickens in the factory is 25% more than that of ducks. How many percent less are ducks than that of chickens?

Let the number of ducks be 1, then the number of chickens is: 1 × (1 + 25%) = 1.25; (1.25-1) △ 1.25 = 0.25 △ 1.25 = 20%; answer: the number of ducks is 20% less than that of chickens

The number of chickens in the factory is 25% more than that of ducks. How many percent less are ducks than that of chickens?

Let the number of ducks be 1, then the number of chickens is: 1 × (1 + 25%) = 1.25; (1.25-1) △ 1.25 = 0.25 △ 1.25 = 20%; answer: the number of ducks is 20% less than that of chickens

The number of chickens is 25% more than that of ducks, and how many percent less than that of chickens?
Number B is 80% of number a, and number a is 20% more than number B. () (√ and ×)
The side length of a square is 25% of its circumference. () (√ and ×)

When the number of ducks is 1, the number of chickens is 1 + 25% = 125%, the number of ducks is less than that of chickens: (125% - 1) △ 125% = 20%, the number of ducks is 80% of the number of ducks, and the number of ducks is 20% of the number of ducks

The number of chickens is 25% more than that of ducks. How many percent less is the number of ducks than that of chickens

The number of ducks is less than that of chickens: (125% - 100%) / 125% = 0.2 = 20%

There are 250 chickens and ducks, four times as many as ducks

Four plus one is five parts, 250 divided by five is 50, 50 times four is 200

There are 68 chickens and ducks in Wang's family, 20 more than ducks. How many chickens and ducks are there

Suppose there are x chickens, then there are 68-x ducks
x=68-x+20
2x=88
x=44
If there are 44 chickens, then 68-44 ducks = 24