The Correct Answer was

9

Explanation

The question did not state that the above expressions were correct. The answer was simply 4+5=9

However, I think this is a very poor answer. Were I the setter of the question, I would treat the + as an unknown operator. A more reasonable answer than the "correct one" would be:

Try

52

Explanation:

Tens digit

is the larger of the two numbers on the LHS, i.e. 5

Units digit

Goes from 1 --(+2+3)(mod10)-> 6 --(+3+4)(mod10)-> 3 --(+4+5)(mod10)-> 2

The Correct Answer was

9

Explanation

The question did not state that the above expressions were correct. The answer was simply 4+5=9

The app is Brain Out, and this is question 58, which answer is shown in this video.

However, I think this is a very poor answer. Were I the setter of the question, I would treat the + as an unknown operator. A more reasonable answer than the "correct one" would be:

Try

52

Explanation:

Tens digit

is the larger of the two numbers on the LHS, i.e. 5

Units digit

Goes from 1 --(+2+3)(mod10)-> 6 --(+3+4)(mod10)-> 3 --(+4+5)(mod10)-> 2

Try

52

Explanation:

Tens digit

is the larger of the two numbers on the LHS, i.e. 5

Units digit

Goes from 1 --(+2+3)(mod10)-> 6 --(+3+4)(mod10)-> 3 --(+4+5)(mod10)-> 2

The Correct Answer was

9

Explanation

The question did not state that the above expressions were correct. The answer was simply 4+5=9

However, I think this is a very poor answer. Were I the setter of the question, I would treat the + as an unknown operator. A more reasonable answer than the "correct one" would be:

Try

52

Explanation:

Tens digit

is the larger of the two numbers on the LHS, i.e. 5

Units digit

Goes from 1 --(+2+3)(mod10)-> 6 --(+3+4)(mod10)-> 3 --(+4+5)(mod10)-> 2