Question

1 2=21
2 3=36
3 4=43
4 5=?

Answer 1

Answer:

from my knowledge,

your answer should be 400.

Answer 2

The missing number(?) is "58".

Explanation:

We have,

1 2 = 21 , 2 3 = 36  and 3 4 = 43  

To find, 4 5 = ?

The pattern follow,

a b  = ba  + 0  or 4 alternatively

1 2 =  21  + 0   = 21

2  3 = 32  + 4  = 36

3  4  = 43  + 0  = 43

Similarly,

∴ ? = 4  5  = 54  + 4  = 58

Thus, the missing number(?) is 58.