Question

7+5=21,10+5=51,and 8+9=?​

Answer 1

Answer:

Your answer is 71.

Yes...When, 7+5=12, It is 21

10+5=15, it is 51

and  when 8+9=17, it is 71.

Nothing special....Just the numbers were swapped...

Answer 2

The missing number = 71

Step-by-step explanation:

We have,

7 + 5 = 21, 10 + 5 = 51

To find, the value of 8 + 9 = ?

The pattern follow:

Sum  of the digits, then the reverse digits.

21 = 7 + 5 = 12 ⇒ Reverse digits = 21

51 = 10 + 5 = 15 ⇒ Reverse digits = 51

Similarly,

? = 8 + 9 =  17 ⇒ Reverse digits = 71

∴ The missing number = 71

Thus, the missing number is 71.