Explanation

10 × 4 = 40

40 × 4 = 160

160 × 4 = 640

640 × 4 = 2560

Explanation

The given series is a square of natural number

(1)^2 = 1

(2)^2 = 4

(3)^2 =9

(4)^2 = 16

(5)^2 = 25

Explanation

The sequence increases by 2 each time. Following this pattern, the next number after 8 is 10.

2 + 2 = 4

4 + 2 = 6

6 + 2 = 8

8 + 2 = 10

Explanation

The series is formed by incrementing the Roman numerals by 3:

V (5) + 3 = VIII (8)

VIII (8) + 3 = XI (11)

XI (11) + 3 = XIV (14)

XIV (14) + 3 = XVII (17)

So, the next number in the series is XVII.

Explanation

The series is formed by adding 1, 2, 3, 4, 5, ... to the previous term, so the next difference should be 5, making the next term:

• 3 + 1 = 4
• 4 + 2 = 6
• 6 + 3 = 9
• 9 + 4 = 13
• 13 + 5 = 18

Therefore, the completed series is: 3, 4, 6, 9, 13, 18.