Question

520,7,121,4,620,8,813,.. next element​

Answer 1

12 is  next to 813 in 520,7,121,4,620,8,813

Given:

• 520,7,121,4,620,8,813

To Find:

• Next number in the series

Solution:

Make the numbers in pairs

(520 , 7) , ( 121 , 4) , (620 , 8)  , ( 813 , ? )

520 , 7

5 + 2 + 0 = 7

121 , 4

1 + 2 + 1 = 4

620 , 8

6 + 2 + 0 = 8

813 , ?

8 + 1 + 3 = 12

Hence 12 will come after 813

Add the Digits of first number and get the second number

Logic is : "Sum of Digits of number at odd position gives the number on the next even position"